Custom bank selection doesn't work on Android 11+

[freq-mod]

File selector doesnt recognize .wopl files, even thought they are in the same directory as MIDI file. Android 11, newest pre-release.
Example, in case needed:
melodic.zip

[Wohlstand]

Android 11 support is needs to be polished separately, the freaking "Scoped Storage" concept needs more to learn to make it usable here, so, on Android 10 and lower should work fine.

[freq-mod]

ah right - tested on Android 9 device, it works

[Wohlstand]

I forgot to mention that I implemented the different file selection thing that works on Android 11+, please test this as soon as possible.