Support Dropbox Team Space

### 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

Add support for accessing team spaces on Dropbox.

### Motivation

Cryptomator is only able to access "personal" folders in Dropbox. In order to add compatibility with business accounts, the support for team spaces should be added.

References:
- https://help.dropbox.com/organize/team-space-overview
- https://www.dropbox.com/developers/documentation/http/teams

### Considered Alternatives

We could also add support for Dropbox team folders but it seems to be deprecated soon.

https://help.dropbox.com/plans/upcoming-business-team-changes

### Anything else?

_No response_

Start by reviewing the existing Dropbox personal-folder support and the linked Dropbox team-space overview and Teams API references. Define completion as allowing business accounts to access team spaces while avoiding the deprecated team-folder path, then verify the relevant account and folder-access behavior.

Written by the indexing model from the issue text.