Build number (part after +) is documented as optional, use entire app version if not present (#37036)

diff --git a/packages/flutter_tools/test/general.shard/flutter_manifest_test.dart b/packages/flutter_tools/test/general.shard/flutter_manifest_test.dart
index d3bb870..231a2b8 100644
--- a/packages/flutter_tools/test/general.shard/flutter_manifest_test.dart
+++ b/packages/flutter_tools/test/general.shard/flutter_manifest_test.dart
@@ -415,6 +415,23 @@
       );
     });
 
+    test('parses major.minor.patch with no build version', () async {
+      const String manifest = '''
+name: test
+version: 0.0.1
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+''';
+      await checkManifestVersion(
+        manifest: manifest,
+        expectedAppVersion: '0.0.1',
+        expectedBuildName: '0.0.1',
+        expectedBuildNumber: null,
+      );
+    });
+
     test('parses major.minor.patch+build version clause 2', () async {
       const String manifest = '''
 name: test