Refactor app version handling and update authentication flow

Previously, this was only triggered when logging in to the application. If a user
just opened the app, it would just stop working. We also now always check this min
version and have removed the option from the android manifest file since disabling
this doesn't make much sense and we have many other platforms as well (iOS, flatpak)

android/app/src/main/AndroidManifest.xml

@@ -29,10 +29,6 @@
         android:enableOnBackInvokedCallback="true"
         android:networkSecurityConfig="@xml/network_security_config">
 
-        <meta-data
-            android:name="wger.check_min_app_version"
-            android:value="true" />
-
         <activity
             android:name=".MainActivity"
             android:exported="true"