GattService: Limit adapterService GATT notification mechanism

With this CL only finder application will be notified to AdapterService
when GATT connection is made.

That means, only this application will be able to connect to LeAudio
device over GATT without making this device auto Active in
AudioFramework.

Bug: 388179850
Bug: 389274300
Flag: com.android.bluetooth.flags.allow_gatt_connect_from_the_apps_without_making_leaudio_device_active
Test: atest GattServiceTest
Change-Id: I3652429800957c79b4e7c5a9d56b77dcb6629285