Cannot remove local copy of file from read-only external mount (Nextcloud Android 3.34.0)

### ⚠️ 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. Configure an external storage mount (e.g. SMB, SFTP, or local folder) on the Nextcloud server with **read-only** permissions.
2. Open the Nextcloud Android client (version 3.34.0).
3. Browse to a file stored in that external storage.
4. Tap the file to open it — it gets downloaded locally.
5. Try to remove the local copy from the device.

### Expected behaviour

The user should be able to remove the local/offline copy from the Android device, even if the external mount is read-only.

### Actual behaviour

There is no option to remove or delete the local copy.
The file remains stored locally even after clearing the cache.
The “Delete” and “Remove from device” options do not appear in the file menu.

### Android version

16

### Device brand and model

Samsung Galaxy Z Fold 7

### Stock or custom OS?

Stock

### Nextcloud android app version

3.34.0

### Nextcloud server version

32.0.0

### Using a reverse proxy?

Yes

### Android logs

_No response_

### Server error logs

```bash

```

### Additional information

There's no log to look at. The button is missing, so I'm unable to perform the action.