Refactor HintManagerService locking to fix race

Bug: 335341012
Test: atest HintManagerServiceTest
Change-Id: I36670f144bc638143ebbe785885ace8aa957f40c
Merged-In: I36670f144bc638143ebbe785885ace8aa957f40c
(cherry picked from commit c0365183554a80b7e7313a33f5d626d797d91b42)
1 file changed