MembershipChangeType Rejoined is probably error prone

[Gnuxie]

Given a user rejecting an invite or being kicked on knock for the first time and later joining again probably shouldn't be classified as rejoined as they never did really join the room. Of course, this relies on transitions being skipped from our perspective due to downtime and not chasing up the chain of events, because normally the user would be classified as renocked or reinvited.