Revert "Migrate some more integration tests to Android embedding v2 (#48532)" (#48582)

This reverts commit 1613a62e85269433682ffc97653d197c50c06240.
diff --git a/dev/integration_tests/image_loading/android/app/src/main/AndroidManifest.xml b/dev/integration_tests/image_loading/android/app/src/main/AndroidManifest.xml
index 5ffd3d3..3002b1b 100644
--- a/dev/integration_tests/image_loading/android/app/src/main/AndroidManifest.xml
+++ b/dev/integration_tests/image_loading/android/app/src/main/AndroidManifest.xml
@@ -28,10 +28,5 @@
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
-    <!-- Don't delete the meta-data below.
-         This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
-        <meta-data
-            android:name="flutterEmbedding"
-            android:value="2" />
     </application>
 </manifest>
diff --git a/dev/integration_tests/image_loading/android/app/src/main/java/com/yourcompany/platforminteraction/MainActivity.java b/dev/integration_tests/image_loading/android/app/src/main/java/com/yourcompany/platforminteraction/MainActivity.java
index d701d4e..37bd362 100644
--- a/dev/integration_tests/image_loading/android/app/src/main/java/com/yourcompany/platforminteraction/MainActivity.java
+++ b/dev/integration_tests/image_loading/android/app/src/main/java/com/yourcompany/platforminteraction/MainActivity.java
@@ -4,14 +4,15 @@
 
 package com.yourcompany.platforminteraction;
 
-import androidx.annotation.NonNull;
-import io.flutter.embedding.android.FlutterActivity;
-import io.flutter.embedding.engine.FlutterEngine;
+import android.os.Bundle;
+import io.flutter.app.FlutterActivity;
 import io.flutter.plugins.GeneratedPluginRegistrant;
+import io.flutter.view.FlutterView;
 
 public class MainActivity extends FlutterActivity {
   @Override
-  public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
-    GeneratedPluginRegistrant.registerWith(flutterEngine);
+  protected void onCreate(Bundle savedInstanceState) {
+      super.onCreate(savedInstanceState);
+      GeneratedPluginRegistrant.registerWith(this);
   }
 }
diff --git a/dev/integration_tests/release_smoke_test/android/app/src/main/AndroidManifest.xml b/dev/integration_tests/release_smoke_test/android/app/src/main/AndroidManifest.xml
index f93ecc4..6d6bc99 100644
--- a/dev/integration_tests/release_smoke_test/android/app/src/main/AndroidManifest.xml
+++ b/dev/integration_tests/release_smoke_test/android/app/src/main/AndroidManifest.xml
@@ -33,10 +33,5 @@
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
-    <!-- Don't delete the meta-data below.
-         This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
-        <meta-data
-            android:name="flutterEmbedding"
-            android:value="2" />
     </application>
 </manifest>
diff --git a/dev/integration_tests/release_smoke_test/android/app/src/main/java/com/example/release_smoke_test/MainActivity.java b/dev/integration_tests/release_smoke_test/android/app/src/main/java/com/example/release_smoke_test/MainActivity.java
index abd9bf8..2d980d6 100644
--- a/dev/integration_tests/release_smoke_test/android/app/src/main/java/com/example/release_smoke_test/MainActivity.java
+++ b/dev/integration_tests/release_smoke_test/android/app/src/main/java/com/example/release_smoke_test/MainActivity.java
@@ -4,14 +4,14 @@
 
 package com.example.release_smoke_test;
 
-import androidx.annotation.NonNull;
-import io.flutter.embedding.android.FlutterActivity;
-import io.flutter.embedding.engine.FlutterEngine;
+import android.os.Bundle;
+import io.flutter.app.FlutterActivity;
 import io.flutter.plugins.GeneratedPluginRegistrant;
 
 public class MainActivity extends FlutterActivity {
   @Override
-  public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
-    GeneratedPluginRegistrant.registerWith(flutterEngine);
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    GeneratedPluginRegistrant.registerWith(this);
   }
 }
diff --git a/dev/integration_tests/ui/android/app/src/main/AndroidManifest.xml b/dev/integration_tests/ui/android/app/src/main/AndroidManifest.xml
index 897ab0c..de54305 100644
--- a/dev/integration_tests/ui/android/app/src/main/AndroidManifest.xml
+++ b/dev/integration_tests/ui/android/app/src/main/AndroidManifest.xml
@@ -28,10 +28,5 @@
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
-    <!-- Don't delete the meta-data below.
-         This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
-        <meta-data
-            android:name="flutterEmbedding"
-            android:value="2" />
     </application>
 </manifest>
diff --git a/dev/integration_tests/ui/android/app/src/main/java/com/yourcompany/integration_ui/MainActivity.java b/dev/integration_tests/ui/android/app/src/main/java/com/yourcompany/integration_ui/MainActivity.java
index cab904f..98f51d4 100644
--- a/dev/integration_tests/ui/android/app/src/main/java/com/yourcompany/integration_ui/MainActivity.java
+++ b/dev/integration_tests/ui/android/app/src/main/java/com/yourcompany/integration_ui/MainActivity.java
@@ -4,14 +4,14 @@
 
 package com.yourcompany.integration_ui;
 
-import androidx.annotation.NonNull;
-import io.flutter.embedding.android.FlutterActivity;
-import io.flutter.embedding.engine.FlutterEngine;
+import android.os.Bundle;
+import io.flutter.app.FlutterActivity;
 import io.flutter.plugins.GeneratedPluginRegistrant;
 
 public class MainActivity extends FlutterActivity {
   @Override
-  public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
-    GeneratedPluginRegistrant.registerWith(flutterEngine);
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    GeneratedPluginRegistrant.registerWith(this);
   }
 }