Crash when playing file that doesn't exist

[BumbleFlash]

Describe the bug
MUSER crashes when it tries to play a file which doesn't exist. Normally, the file won't show up on the collection but if the user has played the song and deleted it, the song is removed from the library but the music player fragment still has the information about it.

To Reproduce
Steps to reproduce the behavior:

1. Go to Muser and play a song.
2. Delete the same song from your phone.
3. Open Muser again and click on Play.

Expected behavior
A dialog showing that the file doesn't exist and upon clicking OK, the user should be redirected to the home screen with the mini music player hidden.

Observed behavior
App crashes to the Launcher upon Clicking Play.

Device and Android version:
Google Pixel 3a. Stock Android 10. Google Play Services 20.18.17