Abandoned read-write flags for profile caching.

Caching flags need to be read only, initialisation check the flags before they are loaded to OS

Bug: 350417399
Bug: 350421409
Bug: 350417403
Bug: 350419395
Change-Id: I4465a2478bce61a53c01a043ad5dc8eb42c8bd4a
Test: N/A
Flag: EXEMPT removing android.multiuser.cache_profile_ids
Flag: EXEMPT removing android.multiuser.cache_profile_type
Flag: EXEMPT removing android.multiuser.cache_profiles
Flag: EXEMPT removing android.multiuser.cache_profile_parent