[BUG] Failure to use Mailbox.org webdav

### Please agree to the following

- [x] I have searched [existing issues](https://github.com/cryptomator/android/issues?q=) for duplicates
- [x] I agree to follow this project's [Code of Conduct](https://github.com/cryptomator/android/blob/develop/.github/CODE_OF_CONDUCT.md)

### Summary

I have tried adding a vault to my Webdav at mailbox.org but I always get a popup stating an error occurred. Sometimes it actually creates a vault file but when I subsequently try to "add an existing vault" I still get an error occured. I've tried going through local storage to my Davx5 mount... An error occurred. I tried adding the Webdav manually in Cryptomator... An error occurred. I use the url "" in Davx5 to add the webdav but cryptomator doesn't accept it. When trying just "https://dav.mailbox.org"... An error occurred. I tried disabling cache and still the same result.

### System Setup

```markdown
- Android: [Version shown in the settings of Android"]
- Cryptomator: [Version shown in the settings of Cryptomator]
- …
```

### Cloud Type

_No response_

### Steps to Reproduce

1. Try webdav with mailbox.org
2. An error occurred.

### Expected Behavior

Work

### Actual Behavior

Doesn't

### Reproducibility

Always

### Relevant Log Output

```shell

```

### Anything else?

Logs sent to support@cryptomator.org