Fix not being able to kick observers in team games

[lL1l1]

Description of the proposed changes

Fixes #6219. Also fixes being able to try to kick the team rating row when there are 3+ teams.

Testing done on the proposed changes

Open two instances of the game. Host multiplayer LAN on a specific port, and connect to localhost:thatport on the other instance (automatic port and discovery doesn't seem to work). Move the second player to observer, and add AIs to change the team sizes (set auto teams to None). Test being able to pop up the kick dialogue only when clicking the observer in all combinations of spawns fixed/not fixed and having 0-3 teams.

Checklist

• [x] Changes are documented in the changelog for the next game version

[Garanas]

Thank you for taking the time and effort to pick this up 👍 , I'll try to review it this weekend.