[macOS] Eliminate unnecessary dynamic declaration (flutter/engine#40327)

Since `view` is a property of `NSViewController`, it's unnecessary for
us to declare `@dynamic view` in `FlutterViewController`'s
implementation.

engine/src/flutter/shell/platform/darwin/macos/framework/Source/FlutterViewController.mm

@@ -318,7 +318,6 @@ void OnKeyboardLayoutChanged(CFNotificationCenterRef center,
 }
 
 @synthesize viewId = _viewId;
-@dynamic view;
 @dynamic accessibilityBridge;
 
 /**