Add "Leave Thread" Option

[HenrickTheBull]

Is your feature request related to a problem? Please describe.

The feature request is related to the problem of being part of a thread and no longer wishing to partake in the thread.

Describe the solution you'd like

An option much like Twitter where you can remove yourself from the thread which would be the hardest mute possible for a thread and it would disallow people from tagging you in the thread again.

Describe alternatives you've considered

There isn't really any alternatives to this. Twitter had something here I think Bluesky could replicate.

Additional context

https://help.twitter.com/en/using-x/mentions-and-replies#mention-control