autoupload: cannot clear obsolete uploads

### Steps to reproduce
1. configure a folder for autoupload
2. change your mind and disable auto upload
3. remove remote folder
4. watch nextcloud app upload all pictures - and showing a conflict (as the destination folder is not there any more)

### Expected behaviour
- remove all pending uploads for folders which don't have an active autoupload config
- or at least allow clearing hundreds of stale auto uploads in the pipeline (clearing with the X did not work as the X was not responsive, due to so many pending uploads)

### Actual behaviour
- the app tries to upload to a non-existing folder, actually consumes bandwith, and shows a conflict for the upload.

### Can you reproduce this problem on https://try.nextcloud.com?
- Please create a test demo account and see if this still happens there.
- If yes, please open up a bug report
- If not, please verify server setup and ask for help on forum

### Environment data
Android version:
11
Device model:
pixel4a
Stock or customized system:
stock
Nextcloud app version:
3.14.0 RC1
Nextcloud server version:
19.0.3
Reverse proxy:

### Logs
#### Web server error log
```
Insert your webserver log here
```

#### Nextcloud log (data/nextcloud.log)
```
Insert your Nextcloud log here
```
**NOTE:** Be super sure to remove sensitive data like passwords, note that everybody can look here! You can use the Issue Template application to prefill some of the required information: https://apps.nextcloud.com/apps/issuetemplate