Auto-upload settings makes it easy to upload duplicate files

### ⚠️ 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. Go to auto-upload settings
2. Enable auto-upload for the "Pictures" folder
3. Enable auto-upload for the "Screenshots" folder
4. Take a screenshot

Screenshots is a subfolder of Pictures/. Not sure why it's listed in auto-upload settings when I've already marked the whole folder for upload.

This makes it really easy to accidentally upload duplicates

### Expected behaviour

The subfolder of Pictures, which I have already enabled for auto-upload, should not be listed in auto-upload settings.

Perhaps a tree of checkboxes is a better UI here?


### Actual behaviour

The subfolder of Pictures, which I have already enabled for auto-upload, is listed as an option in auto-upload settings.

### Android version

15

### Device brand and model

Pixel 7 Pro

### Stock or custom OS?

Custom (explain in "additional information")

### Nextcloud android app version

3.30.5

### Nextcloud server version

30.0.2

### Using a reverse proxy?

Yes

### Android logs

_No response_

### Server error logs

```bash

```

### Additional information

CalyxOS

从自动上传设置流程开始，在 Android 上使用 Pictures 及其子文件夹 Screenshots 重现这些步骤。完成标准是：已由启用的父文件夹覆盖的子文件夹不再作为单独的上传选项提供，同时不会导致重复上传。

由索引模型根据 Issue 内容生成。