on team switch form, team still displays as available when they are full

[jessie-jin]

Issue:

In the Team Switch Form, teams still display as available regardless of whether or not they are over the team size limit. We do not want people trying to switch to a team that is already full.

Reproducing the bug:

On http://localhost:3000/teamswitch, in the Team Switch Form:

Even if one of the teams is not available, both times still display on the Team Switch Form. We want to be able to set a time size limit, so that the team's practice times will not display in the Team Switch Form if the team is over the limit.

Solution:

We want to prevent teams from showing up on the team switch form if the size of the team is larger than a certain number. To do this, we will add a check to see if this is the case when we add/drop dancers. That updates a boolean variable, and that allows us to change whether or not the team practice time displays in the form.