Experiment Cleanup: invite_members_in_side_nav"

What does this MR do and why?

Related to #393199 (closed)

This MR is to remove the experiment: invite_members_in_side_nav.

Screenshots or screen recordings

Please see screenshots of candidate experience here: !70451 (merged)

Removing this experiment does not change the UI.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.