[CRASH] App crashed when I am in uploads screen, go back to main activity and then click upload from nav drawer

### ⚠️ 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. I use SSL self signed verification for my nextcloud webapp, no in my app notification it showed SSL verification failed. I clicked that, nothing happened.
2. Selected nextcloud app again
3. Goto uploads page
4. Selected 1 skipped file (file had a message as a file with the same name exists)
5. It took me back to the main activity with a toast message Retrieving file...
6. Before the file load i opened nav drawer and selected uploads again
7. Then it crashed.

### Expected behaviour

It should open the uploads page or block me from opening any other screens till the retrieving file is completed.

### Actual behaviour

If have option to select other menu items so I selected, and got app crash message.

### Android version

16

### Device brand and model

Samsung S25

### Stock or custom OS?

Stock

### Nextcloud android app version

3.35.2

### Nextcloud server version

32.0.5

### Using a reverse proxy?

I don't know

### Android logs

_No response_

### Server error logs

```bash

```

### Additional information

_No response_