statsd checks permissions using SCS

The checkCallingPermission function is not supported by libbinder_ndk.
To circumvent this issue, statsd will now ask StatsCompanionService
(SCS) to do that check using a synchronous Binder call. Once
libbinder_ndk does support checkCallingPermission, this workaround will
be unnecessary.

Test: m -j
Test: atest GtsStatsdHostTestCases
Bug: 145566180
Change-Id: I11f0e82f88aa5921cf531fd041b0a18d3a26a0a0