Update transport connection with registration info

When connecting to a transport, let the transport
know if this connection is for registration. This is to
prevent updating transport attributes during registration
in GMSCore.

Bug: 72730566
Test: 1) m -j ROBOTEST_FILTER=TransportManagerTest RunFrameworksServicesRoboTests
2) m -j ROBOTEST_FILTER=TransportClientManagerTest RunFrameworksServicesRoboTests
3) adb reboot; adb logcat | grep BackupTransportManager; check no errors with "...not registered tried to change description"
4) GMSCore Robo tests
Change-Id: I5adf6ea3e668a8e8ed8c568728d109814b6f8975