Issue with certificate while traveling

### Actual behaviour
-Tell us what happens
I just came from a trip and at the hotel I wanted to get access to the WiFi. I had the required credential to get WiFi up and running, but I have noticed the following:

- I was able to connect to the WiFi access point but I need to enter the credential to access the Internet (which I didn't do right away) because the signin pages is to slow to popup.
- I then start NC and upon starting it, I get a dialog requesting to accept or decline the certificate. At this point NC believes it has to update the certificate which is not true as the certificate on my server and my NC account on the phone have not been updated.

- For me to access NC, I have to enter the credential for the access point.
- I can then access NC.

### Expected behaviour
-Tell us what should happen
NC shouldn't mess with the certificate when it is connected to an access point without Internet access. Internet access should be available once credential of the access point are specified.

### Steps to reproduce
1. See above
2.
3.

### Environment data
Android version:
6.0
Device model:
LG3
Stock or customized system:
Stock
Nextcloud app version:
2.0.0RC8
Nextcloud server version:
12.3
### Logs
#### Web server error log
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#### Nextcloud log (data/nextcloud.log)
```
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