Reinstate the EMS square on the server selection screen

### Your use case

We previously chose to hide it: https://github.com/vector-im/element-ios/issues/6150

This issue is a placeholder to reinstate it when we've been unblocked and have the time to do so.

### Have you considered any alternatives?

_No response_

### Additional context

_No response_

Start by reading issue #6150 to understand why the EMS square was hidden and what must be unblocked. Then locate the server selection screen in the iOS app and confirm the expected EMS square behavior; done means the square is reinstated without violating the constraints described in the related issue.

Written by the indexing model from the issue text.