Make prev/next headset buttons configurable

[dvalter]

Also changes behavior of A13+ player notification buttons.

and improves

What is it?

• [ ] Bugfix (user facing)
• [x] Feature (user facing)
• [ ] Codebase improvement (dev facing)
• [ ] Meta improvement to the project (dev facing)

Description of the changes in your PR

• Adds setting for prev/next track headset actions. Fixes #7880
• Also applies the same actions to Android 13+ player notification fixed buttons. Fixes regression in #10712 fix of #9764

Before/After Screenshots/Screen Record

• Before:
• After:

Fixes the following issue(s)

• Fixes #7880

APK testing

The APK can be found by going to the "Checks" tab below the title. On the left pane, click on "CI", scroll down to "artifacts" and click "app" to download the zip file which contains the debug APK of this PR. You can find more info and a video demonstration on this wiki page.

Due diligence

• [x] I read the contribution guidelines.

[dvalter]

The only drawback is that it's seemingly impossible to change the appearance of the notification buttons on A13 without making all actions custom like in #10580.

However in that case headset functionality can be restored via an overridden MediaButtonEventHandler

[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[dvalter]

Looks like the tests has failed for some unrelated reasons. One due to some access issues and the other in the test that should not be affected by my changes.