Refine the name of onInsetsModified

It won't get called on every insets change, but will only get called
when the requested visible types is changed. This CL renames it to
onRequestedVisibleTypesChanged.

Fix: 282682000
Bug: 282128806
Test: atest InsetsStateControllerTest
Change-Id: I5924bf03c5e1ba682d0bb271e32992b0a7290808