This is a workaround for the new scoped storage design in Android 11:

 https://developer.android.com/about/versions/11/privacy/storage

This needs a proper solution eventually, but this quick fix will do
until we change "targetSdkVersion" to 30.

Closes https://github.com/MusicPlayerDaemon/MPD/issues/1061

The Google overlords require me to change to 29 or else I can't upload
new releases to Google Play.

 https://developer.android.com/distribute/best-practices/develop/target-sdk

TODO: Not sure the app could be accepted on the play store without a valid
banner.

This seems to be required on recent Android versions (tested with Android 10).
This is also required for android TV services (cf. next commit).

This is done using Java reflection so that the project doesn't depend on
android compat libs.

Google Play refuses uploads with a lower targetSdkVersion.