Cache quiet mode state in UserManager

This CL adds a cache for the quiet mode state in UserManager. The cache is invalidated when the quiet mode state is changed. This change should improve the performance of the isQuietModeEnabled method.

Bug: 350420769
Change-Id: Iba99b30f36447dd1998fc418b8d59b80076ba8b9
Test: atest QuietModeTest
Test: atest ManagedProfileQuietModeEnablerTest
Flag: android.multiuser.cache_quiet_mode_state