Jts/1989 invite suggestions

[JohnSimonsen]

Ensure suggestions in InviteDialog to only show members of the current space

This PR adds another layer of filtering of the "Recents" and "Sugested" lists

• Creates a list of userIds of the currently selected space
• Uses the list to filter what is added or returned in buildRecents and buildSuggestions

Originally I think the plan was to clear the store on context switch (switching spaces)
But as the InviteDialog builds the lists on render, and by creating a list of possible suggestions using members of all rooms available. I that could be more dificult. So instead i modified the buildRecents and buildSuggestions methods slightly.

Checklist

• Tests written for new code (and old code if feasible).
• New or updated public/exported symbols have accurate TSDoc documentation.
• Linter and other CI checks pass.
• Sign-off given on the changes (see CONTRIBUTING.md).