[View Controllers] (2/3) Move KSBVC's visibility and shouldUpdate calculation

out of NPVController and into KSBVC.

Test: atest (+ new unit tests) and manual
Bug: 195442899
Change-Id: I0a88132293dd5a083122a3fd971a5bbc6487355f
Merged-In: I0a88132293dd5a083122a3fd971a5bbc6487355f