new media view stalls the UI when launched

### Steps to reproduce
1. Go to the hamburger menu
2. Open the media view
3.

### Expected behaviour
- pictures should be visible instantly, at least those on the device, better at least all that are already known to the client since they have been loaded before
- "gathering pictures" or similar should be shown if pictures cannot be shown instantly, e.g. first start-up and no local pictures.

### Actual behaviour
- The UI stalls for more than 15 seconds

### Environment data
Android version: 12

Device model: Pixel 4a

Stock or customized system: stock

Nextcloud app version: 3.20

Nextcloud server version: 23.0.4

Reverse proxy: apache

### Logs
#### Web server error log
```
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#### 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