Heic files not uploading

### ⚠️ 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

The Nextcloud Android app doesn't upload heic files to the server, these end up in the failed/ retry list.

### Expected behaviour

Upload heic files to the server.

### Actual behaviour

Heic files not uploading, they end up in the failed/ retry list.

### Android version

16

### Device brand and model

Samsung galaxy s25 ultra

### Stock or custom OS?

Stock

### Nextcloud android app version

34.1.1

### Nextcloud server version

Spring 26 hub

### Using a reverse proxy?

Yes

### Android logs

_No response_

### Server error logs

```bash

```

### Additional information

_No response_

Start by reproducing the HEIC upload failure in the Nextcloud Android app version 34.1.1 on the reported Android 16 setup, then inspect how failed uploads enter the failed/retry list. Done means HEIC files upload successfully to the server instead of being queued for retry; Android or server logs are needed to narrow the failing path.

Written by the indexing model from the issue text.