Files being renamed upon "share to" upload in 34.1.0

### ⚠️ 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

Steps to reproduce:
- Open file/image in e.g. gallery app
- check the file name
- click "share to" button
- select Nextcloud app
- check upload file name

### Expected behaviour

File name should remain unaltered and original file name must be preserved. The issue occurs since app was updated yesterday, Previous version of the app allowed upload with original file name.

### Actual behaviour

original file name was e.g. IMG_20260724_095541.jpg (date/time based format). In the upload dialog Nextcloud App suggest file name such as 1784890751676.jpg (looks like timestamp format).

### Android version

Xiaomi HyperOS 3.0.304 / Android 16 with security update 2026-06-01

### Device brand and model

Redmit Note 14 Pro+ 5G

### Stock or custom OS?

Stock

### Nextcloud android app version

34.1.0

### Nextcloud server version

33.0.7

### Using a reverse proxy?

No

### Android logs

`adb logcat --pid=$(adb shell pidof -s 'com.nextcloud.client')` produces no log output during this operation.

### Server error logs

```bash
n/a (issue is client side only and occurs before upload)
```

### Additional information

_No response_

Start by reproducing the Android "share to" upload flow described in the issue and inspect where the upload dialog obtains its filename. Compare the selected file's original name with the suggested name, then verify that sharing a file preserves its original filename before upload.

Written by the indexing model from the issue text.