[web] Remove friend request suggestion in sidebar chats

Summary:
Linear

previously the RelationshipPrompt component was getting rendered in sidebar chats on web. This diff adds the proper check to prevent this behavior.

Test Plan:
Before:

After:

Test ensuring that relationship prompt still shows on Personal threads

Reviewers: atul, tomek

Reviewed By: tomek

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D5761