Add shouldDockBigOverlays API

This CLs provides the getter API for DockBigOverlays. To better follow
API guidelines, it changes the naming from "*preferDockBigOverlays" to
"*shouldDockBigOverlays"

Bug: 220739302
Test: atest PinnedStackTests#testShouldDockBigOverlaysWithExpandedPip
Change-Id: I25c18531bc1f386b208ab7dde81a8b11a22d03a1
9 files changed