Only show shimmer on non active chat tabs

Currently:
When multiple chats are in progress within a session, there's an overload of progress indicators.

Solution:
When a chat tab is in focus, that is also in progress, don't show progress indication at the tab level. Since that will already be taken care of by the in-progress response in the chat view.

Show the chat title shimmer, when the chat tab is not in focus.
Keep this shimmer visible in the "Chats" list as well (in case user soft closes one of the chat tabs).