Consider case of meeting type dropdown when queue only allows one option

[ssciolla]

@janelilr provided the following feedback as part of her June 2023 usability review.

Managing a specific queue page
Current: Zoom dropdown is available, but there is only one option
Suggestion: If there is only one option available, remove the caret
Reason: caret dropdown indicates there are multiple options and can be confusing that there is only one option available
Minor usability issue

This would require refactoring of the BackendSelector component in meetingType.tsx, or maybe just not using that component when there's only one option.

[xinzhouhe]

Hi, we are a pair of students from EECS 481 and we would like to claim this issue, is it still open? Thank you.