Remove tests related to StrictMode that were never running on CI. (#51827)

Closes flutter/flutter#60635 as not planned.

Author: matanlurey

testing/scenario_app/android/BUILD.gn

@@ -29,7 +29,6 @@ _android_sources = [
   "app/src/main/java/dev/flutter/scenarios/PlatformViewsActivity.java",
   "app/src/main/java/dev/flutter/scenarios/SpawnMultiEngineActivity.java",
   "app/src/main/java/dev/flutter/scenarios/SpawnedEngineActivity.java",
-  "app/src/main/java/dev/flutter/scenarios/StrictModeFlutterActivity.java",
   "app/src/main/java/dev/flutter/scenarios/SurfacePlatformViewFactory.java",
   "app/src/main/java/dev/flutter/scenarios/TestActivity.java",
   "app/src/main/java/dev/flutter/scenarios/TestableFlutterActivity.java",

testing/scenario_app/android/app/src/main/AndroidManifest.xml

@@ -59,17 +59,6 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
-        <activity android:name=".StrictModeFlutterActivity"
-            android:launchMode="singleTop"
-            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
-            android:hardwareAccelerated="true"
-            android:exported="true">
-            <intent-filter>
-                <!-- TODO: https://github.com/flutter/flutter/issues/60635 -->
-                <action android:name="dev.flutter.scenarios.STRICT_MODE" />
-                <category android:name="android.intent.category.LAUNCHER" />
-            </intent-filter>
-        </activity>
         <activity
             android:name=".GetBitmapActivity"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"