Fix by Alper

Signed-off-by: Jonas Mayer <jonas.a.mayer@gmx.net>

app/src/main/AndroidManifest.xml

@@ -121,6 +121,7 @@
         android:requestLegacyExternalStorage="true"
         android:roundIcon="@mipmap/ic_launcher"
         android:supportsRtl="true"
+        android:enableOnBackInvokedCallback="false"
         android:theme="@style/Theme.ownCloud.Toolbar"
         android:usesCleartextTraffic="true"
         tools:ignore="UnusedAttribute"