Switching network causes current file upload failure

### Steps to reproduce
1. Start (multiple) file uploading on wifi
2. Switch network to mobile (manually or by leaving wifi network area) while uploading is in progress

### Expected behaviour
- App should put current transfer activity on hold until connectivity to server is restored

### Actual behaviour
Currently uploaded file gets skipped to next one with errors:
- uploader_upload_failed_ticker
- auth_ssl_general_error_title

### Can you reproduce this problem on https://try.nextcloud.com?
Will try (and get back with the results)

### Environment data
Android version: 12

Device model: Samsung Note 10+ (SM-N975F)

Stock or customized system: Stock

Nextcloud app version: 3.18.1

Nextcloud server version: 23.0.0

Reverse proxy: N/A

### Logs
#### Web server error log
```
[Fri Jan 14 00:35:13.200674 2022] [ssl:emerg] [pid 127786] AH02572: Failed to configure at least one certificate and key for nextcloud.*:443
[Fri Jan 14 00:35:13.200701 2022] [ssl:emerg] [pid 127786] SSL Library Error: error:140A80B1:SSL routines:SSL_CTX_check_private_key:no certificate assigned
[Fri Jan 14 00:35:13.333887 2022] [ssl:emerg] [pid 127793] AH02572: Failed to configure at least one certificate and key for nextcloud.*:443
[Fri Jan 14 00:35:13.333925 2022] [ssl:emerg] [pid 127793] SSL Library Error: error:140A80B1:SSL routines:SSL_CTX_check_private_key:no certificate assigned
[Fri Jan 14 00:37:22.520998 2022] [ssl:emerg] [pid 127827] AH02572: Failed to configure at least one certificate and key for nextcloud.*:443
[Fri Jan 14 00:37:22.521021 2022] [ssl:emerg] [pid 127827] SSL Library Error: error:140A80B1:SSL routines:SSL_CTX_check_private_key:no certificate assigned
```

#### Nextcloud log (data/nextcloud.log)
```
{"reqId":"mmqah3mPLxitgsuKy7Qk","level":2,"time":"2021-08-12T09:21:49+00:00","remoteAddr":"::1","user":"--","app":"no app in context","method":"GET","url":"/nextcloud/","message":"Host localhost was not connected to because it violates local access rules","userAgent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.134 Safari/537.36","version":""}
{"reqId":"mmqah3mPLxitgsuKy7Qk","level":2,"time":"2021-08-12T09:21:49+00:00","remoteAddr":"::1","user":"--","app":"no app in context","method":"GET","url":"/nextcloud/","message":"Host localhost was not connected to because it violates local access rules","userAgent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.134 Safari/537.36","version":""}
{"reqId":"bSgi5DsYHUX2uB08CNbY","level":2,"time":"2021-08-12T09:23:24+00:00","remoteAddr":"::1","user":"--","app":"no app in context","method":"POST","url":"/nextcloud/index.php","message":"Host localhost was not connected to because it violates local access rules","userAgent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.134 Safari/537.36","version":""}
{"reqId":"bSgi5DsYHUX2uB08CNbY","level":2,"time":"2021-08-12T09:23:24+00:00","remoteAddr":"::1","user":"--","app":"no app in context","method":"POST","url":"/nextcloud/index.php","message":"Host localhost was not connected to because it violates local access rules","userAgent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.134 Safari/537.36","version":""}
```
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