Add Proton Drive support

### Please agree to the following

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

### Summary

Proton Drive not selectable in iOS files app

### System Setup

- iOS: 17.4.1
- Cryptomator: 2.5.1
- Proton Drive iOS app (latest iOS App Store version, and also latest TestFlight Version 1.28)

### Cloud Type

Other File Provider

### Steps to Reproduce

1. In the iOS files app, select Proton Drive to be available in the list of file provider
2. Open Cryptomator and add an existing vault
3. Select other file provider
4. Proton Drive is shown in the Files app but can not be selected

### Expected Behavior

Select Proton Drive in the Files app and slelect existing vault

### Actual Behavior

Proton Drive can not be chosen as a file provicer in Cryptomator

### Reproducibility

Always

### Relevant Log Output

_No response_

### Anything else?

_No response_