Added android:exported="true" to the example Android manifest

This is needed for targeting Android 12 (API 31)

android-project/app/src/main/AndroidManifest.xml

@@ -72,6 +72,7 @@
             android:launchMode="singleInstance"
             android:configChanges="layoutDirection|locale|orientation|uiMode|screenLayout|screenSize|smallestScreenSize|keyboard|keyboardHidden|navigation"
             android:preferMinimalPostProcessing="true"
+            android:exported="true"
             >
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />