Upgraded gradle version and configuration files

android/app/src/main/AndroidManifest.xml

@@ -1,6 +1,5 @@
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="eu.mhsl.marianum.mobile.client">
-   <application
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <application
         android:label="Marianum Fulda"
         android:name="${applicationName}"
         android:icon="@mipmap/ic_launcher">
@@ -31,5 +30,16 @@
             android:name="flutterEmbedding"
             android:value="2" />
     </application>
+    <!-- Required to query activities that can process text, see:
+         https://developer.android.com/training/package-visibility?hl=en and
+         https://developer.android.com/reference/android/content/Intent#ACTION_PROCESS_TEXT.
+
+         In particular, this is used by the Flutter engine in io.flutter.plugin.text.ProcessTextPlugin. -->
+    <queries>
+        <intent>
+            <action android:name="android.intent.action.PROCESS_TEXT"/>
+            <data android:mimeType="text/plain"/>
+        </intent>
+    </queries>
     <uses-permission android:name="android.permission.INTERNET"/>
 </manifest>