Fixed UID mismatch in telephony registry

Telephony registry is running in the system process. When receiving
the binder call from phone, after checking the permission, it should
perform actions in system's identity.

Bug: 271892778
Test: Boot up
Test: Basic phone functionality tests
Test: atest TelephonyRegistryTest
Change-Id: I761b9a73f7654eea14d08f7d2602978d32aedffc
Merged-In: I761b9a73f7654eea14d08f7d2602978d32aedffc