[ios] Convert `int` in Dart to `long long` in Objective-C. (#39331)

For native targets, an `int` in Dart maps to a signed 64-bit integer representation.
diff --git a/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm b/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm
index 8df862e..2612c13 100644
--- a/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm
+++ b/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm
@@ -193,14 +193,14 @@
 void FlutterPlatformViewsController::OnCreate(FlutterMethodCall* call, FlutterResult& result) {
   NSDictionary<NSString*, id>* args = [call arguments];
 
-  long viewId = [args[@"id"] longValue];
+  int64_t viewId = [args[@"id"] longLongValue];
   NSString* viewTypeString = args[@"viewType"];
   std::string viewType(viewTypeString.UTF8String);
 
   if (views_.count(viewId) != 0) {
     result([FlutterError errorWithCode:@"recreating_view"
                                message:@"trying to create an already created view"
-                               details:[NSString stringWithFormat:@"view id: '%ld'", viewId]]);
+                               details:[NSString stringWithFormat:@"view id: '%lld'", viewId]]);
   }
 
   NSObject<FlutterPlatformViewFactory>* factory = factories_[viewType].get();
@@ -234,7 +234,8 @@
                                                                 arguments:params];
   UIView* platform_view = [embedded_view view];
   // Set a unique view identifier, so the platform view can be identified in unit tests.
-  platform_view.accessibilityIdentifier = [NSString stringWithFormat:@"platform_view[%ld]", viewId];
+  platform_view.accessibilityIdentifier =
+      [NSString stringWithFormat:@"platform_view[%lld]", viewId];
   views_[viewId] = fml::scoped_nsobject<NSObject<FlutterPlatformView>>([embedded_view retain]);
 
   FlutterTouchInterceptingView* touch_interceptor = [[[FlutterTouchInterceptingView alloc]
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterPlatformViewController.mm b/shell/platform/darwin/macos/framework/Source/FlutterPlatformViewController.mm
index ac01ef5..ba2399a 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterPlatformViewController.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterPlatformViewController.mm
@@ -90,7 +90,7 @@
   if ([[call method] isEqualToString:@"create"]) {
     NSMutableDictionary<NSString*, id>* args = [call arguments];
     if ([args objectForKey:@"id"]) {
-      int64_t viewId = [args[@"id"] longValue];
+      int64_t viewId = [args[@"id"] longLongValue];
       NSString* viewType = [NSString stringWithUTF8String:([args[@"viewType"] UTF8String])];
       [self onCreateWithViewID:viewId viewType:viewType result:result];
     } else {
@@ -100,7 +100,7 @@
     }
   } else if ([[call method] isEqualToString:@"dispose"]) {
     NSNumber* arg = [call arguments];
-    int64_t viewId = [arg longValue];
+    int64_t viewId = [arg longLongValue];
     [self onDisposeWithViewID:viewId result:result];
   } else {
     result(FlutterMethodNotImplemented);