[BUG] FLATPAK - All logins lost upon app relaunch

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Describe the bug
All logins/credentials/authorization to 3rd party services fail upon app relaunch

To Reproduce
Steps to reproduce the behavior:

1. Logged into YT, Spotify, LastFM successfully (confirmed that playlists and scrobbles were showing)
2. Quit Moosync.
3. Re-open Moosync.
4. All accounts are logged out, playlists gone.
5. Logging back in is a pain, and the google re-authorization attempt is blocked when Firefox is the default browser.

Expected behavior
When the app restarts after being quit, it should use the provided client IDs and secrets to log back in and show the associated playlists etc.

Screenshots
If applicable, add screenshots to help explain your problem.

• OS: Linux Mint 21.3
• Moosync Version 10.3.2 Flatpak

Additional context

[Ao1Pointblank]

I switched to the .deb install method and it all works fine. probably just a typical flatpak sandboxing issue.