Flatpak: Cannot open files when built as Flatpak

[jeremypw]

What Happened?

Built the app as a Flatpak from the main branch. App launches OK, but when a music file is dropped onto the queue or activated in the filemanager it is flagged as invalid by Music and nothing plays.

Steps to Reproduce

1. Build and run Music as a flatpak using the supplied manifest
2. Drag/Drop a music file from the user Music folder onto the queue
3. Use the Files "Open with" context menu on an audio file to launch it in Music
4. In each case the file is flagged as invalid and does not play

Expected Behavior

Music v7 and later should run as a Flatpak and still be able to play audio files from the users Music folder

OS Version

7.x (Horus)

Software Version

Compiled from git

Log Output

No response

Hardware Info

No response

[jeremypw]

Fixed by #747