Upload conflict dialog doesn't display server file's thumbnail

### ⚠️ 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

Gize,

What am I supposed to do with this?

W/out the matching image on the right side it doesn't matter that the date and file size might be the same, it could be any other image not even related the the one on the left.

And notice I have over 3300(!) to individually go through just like it! lol

If I DON'T then I get to enjoy the 24/7/365 notification in my bad letting me know to get to it....

We need to be able to see the image it's being compared to as well.

### Expected behaviour

TBH if it's an exact match (i.e. matching SHA256 (or similar)) then don't even bother me at all. ;)

### Actual behaviour

See first comment

### Android version

16

### Device brand and model

Samsung Galaxy S22 Fold Z

### Stock or custom OS?

Stock

### Nextcloud android app version

34.0.1 RC1

### Nextcloud server version

34.0.0

### Using a reverse proxy?

Yes

### Android logs

_No response_

### Server error logs

```bash

```

### Additional information

_No response_

Start by reproducing the upload conflict dialog described in the issue and trace the code that loads the server-side file preview. Done means the dialog displays the server file's thumbnail for comparison; check the linked pull request and existing conflict-dialog tests or entry points before starting, since work may already have moved there.

Written by the indexing model from the issue text.