DIS-2809: Reduce unnecessary API calls

[catsoup11789]

Many of these will be hard to test the benefit of, but if you're tracking API requests in Aspen Discovery or have a console log, you should see significantly less repetitive entries. Just noting the individual changes here to update test notes later and whether or not we need to update any documentation....

• GroupedWork: Only prefetch data for first format. Switching to another format should trigger a new set of API calls and there will be no missing data or unexpected results.
• MyHolds & MyCheckouts: Removed background fetch on Drawer which was pointless when we force refetch whenever loading the Holds/Checkouts screen. Side effect of this unnecessary background fetch was it also updated when Language was updated, when we still only need it when going to that screen.
• MyHolds: It previously polled validPickupLocations for every hold on screen load, now it will only do so if the user goes to change pickup location for a hold (and only for that hold)
• MyList: We were previously fetching list details twice when opening a list; make sure list data still loads in as expected
• MyLibraryCard: We were making unnecessary (3+) calls to updateScreenBrightnessStatus when leaving the screen; this is related to storing on the user table if we should ask them for permission...
• Home: We called getDefaultFacets, getSearchIndexes, and getSearchSources every time this screen was loaded, when it's very doubtful any of these values would change in the same session -- setup for the Search Results facets
• MySavedSearches - We were fetching getSavedSearches twice when loading the screen every time; make sure list of saved searches populates as expected