Update location broadcast behavior

Updates location broadcast behavior in preparation for future changes
that will remove writes to LOCATION_PROVIDERS_ALLOWED. These changes
ensure that clients can properly listen for changes to provider enabled
status without being reliant on the deprecated
LOCATION_PROVIDERS_ALLOWED.

Bug: 145752928
Test: presubmits
Change-Id: I073749a895a6a206023290d83ea815a361353460