Audio keeps playing when exiting player view

### ⚠️ Before posting ⚠️

- [x] This is a **bug**, not a question or an enhancement.
- [x] I've [searched for similar issues](https://github.com/nextcloud/android/issues) and didn't find a duplicate.
- [x] I've written a clear and descriptive title for this issue, not just "Bug" or "Crash".
- [x] I agree to follow Nextcloud's [Code of Conduct](https://nextcloud.com/contribute/code-of-conduct/).

### Steps to reproduce

1. Tap on an audio file in the file list
2. Wait for audio to start playing
3. Perform an action that makes you exit the player, like pressing the back button (OS or in-app) or deleting the file.
4. Audio keeps playing and the only way to get it to stop is to either exit the app or tap on a file again.

### Expected behaviour

The audio should stop playing once the user has exited the player.

### Actual behaviour

The audio keeps playing.

### Android version

16

### Device brand and model

Fairphone 4

### Stock or custom OS?

Custom (explain in "additional information")

### Nextcloud android app version

33.0.1 (reproducible on latest dev as well)

### Nextcloud server version

Hub 25 Autumn

### Using a reverse proxy?

Yes

### Android logs

[Nextcloud Android Files Logs.txt](https://github.com/user-attachments/files/26345075/Nextcloud.Android.Files.Logs.txt)

### Server error logs

```bash

```

### Additional information

I run LineageOS 23.2 on my phone, but I doubt that is relevant as a friend of mine who runs stock Samsung Android can also reproduce this issue.