Rename cellbroadcast's authority and fix permission check

Reanme the cellbroadcast's authority to cellbroadcasts_fwk to resolve
the conflict between this provider and cellbroadcast receiver app. This
provider will be eventually removed. The public application should use
the provider in cellbroadcast receiver app to get the cellbroadcast
message.

Only phone process can access this provider.

Bug: 123096618
Test: build
Merged-In: I9447cec0a261c790ac06e83a309268ceac4313df
Change-Id: I9447cec0a261c790ac06e83a309268ceac4313df
(cherry picked from commit de88c3af0b7936f49aebdf243a61f70001724480)
3 files changed