[FRONTEND] Blur booking calendar when availabilities are still loading

[bcho892]

Is your feature request related to a problem? Please describe.

will need to use the isLoading property in client\src\components\composite\Booking\BookingCreation\ProtectedCreateBookingSection.tsx from useAvailableBookingsQuery

BEFORE MERGING

• [ ] Storybooks created where possible
• [ ] Tested with nock if data fetching
• [ ] Tests written for critical interactions
• [ ] PR Reviewed (For non-trivial changes)
• [ ] Changes tested after rebasing on master or merging in master (hint: git fetch origin master:master, then git rebase master or git merge master)
• [ ] All required PR checks passing

[bcho892]

The UX isn't too bad right now, and the blur may not be the best experience