Create array of all insets types

This replaces the current insets type iteration based on first and last
values with an array iteration, enabling IntDef flag value checks, and
making the code more readable.

Flag: EXEMPT refactor
Bug: 281029564
Test: atest WindowInsetsTest InsetsSourceTest
Change-Id: I034197f61e2e44a33f35be8b6130bc8760479f19