File Upload adds testfolders without deleting the afterwards

### ⚠️ 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

Open nc app on android
Click on +
Click on dateien hochladen (file upload)
Navigate through folders
In each folder you'll see an empty folder named .test_write_dir_{number} while the nc app displays a message "Upload Option: Quellverzeichnis ist nur lesbar; Datei wird nur hochgeladen"

### Expected behaviour

Testfolder will be deleted after the test and the obviously wrong message, claiming read only while creating folders, is not displayed

### Actual behaviour

Like described in the steps to reproduce

### Android version

16

### Device brand and model

Samsung S23

### Stock or custom OS?

Stock

### Nextcloud android app version

33.1.0

### Nextcloud server version

33.0.0.16

### Using a reverse proxy?

Yes

### Android logs

Sorry, could just use logcat

### Server error logs

```bash

```

### Additional information

_No response_