Fix missing android:exported attributes in AndroidManifest.xml (mandatory in Android >= 12).

Author: touilleMan

samples/app/src/main/AndroidManifest.xml

@@ -11,7 +11,8 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
-        <activity android:name=".MainActivity">
+        <activity android:name=".MainActivity"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />