Participants > Groups: Performance needs to be improved

[MSoeb]

Description: The group permission menu lacks in performance, if more and more groups were added to the meeting.

Reproduction:

1. open a meeting
2. open participants > three-dot-menu > groups
3. add more groups and see how the performance of the page goes down. scrolling gets slower and slower with every added group.

What should happen:
The amount of groups in the permissions menu shouldn't have such a negative performance effect. It should by okay to have around 15 groups without performance issues.

[rrenkert]

@MSoeb can you please test this again?