New text document filename dialog broken

### ⚠️ 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. In any folder click + then new text file
2. Edit the filename and change extension to .md
3. See error message (cant change ending), try changing it back - nothing happening, OK stays disabled, no change of the filename will ever bring it back. app restart did not help. app reinstall did not help either.

### Expected behaviour

Firstly .md is also a text document but whatever. If you check the filename please do it after clicking ok and do not disable the ok button.

### Actual behaviour

ok button stays disabled.

### Android version

16

### Device brand and model

Pixel 6

### Stock or custom OS?

Stock

### Nextcloud android app version

33.1.1

### Nextcloud server version

33.1.1

### Using a reverse proxy?

No

### Android logs

_No response_

### Server error logs

```bash

```

### Additional information

_No response_