Automatic upload failed due to missing folder

### Steps to reproduce
1. Activate Automatic upload from camera folder to Nextcloud folder 'Photos'
2. Take photo
3. App creates a sub folder with Year and date in Nextcloud Photos folder
4. The automatic upload works normal
5. Close Nextcloud app
6. delete the Nextcloud sub folders under Photos using another computers browser
7. Open smartphone camera and take a new photo
8. Upload faileds, because the Nextcloud app did not notice that the sub folder year and date does not exist any more and tries to upload the new photo into non existing folder.

Work around: open the Android app once and let it rescann the folders at the server. Then the app notices, that the sub folder does not exist.

### Expected behaviour
When automatic upload happens the app should scan the server first for changes .

### Actual behaviour
The autonatic uploads uploads the files without checking for changes on the server

### Can you reproduce this problem on https://try.nextcloud.com?
- Please create a test demo account and see if this still happens there.

Not possible to connect the Android app to the test account.

- If yes, please open up a bug report
- If not, please verify server setup and ask for help on forum

### Environment data
Android version:
8
Device model:
Samsung S7 Flat
Stock or customized system:
Stock
Nextcloud app version:
3.11.0
Nextcloud server version:
18.03
Reverse proxy:
N.a.
### 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