SystemServer: implement getState for general purpose

Fetching the Bluetooth state cannot be a oneway call, but some system
process are making the call anyway.
By moving the getter into the SystemServer, we are ensuring that the non
oneway call can be executed.

Bug: 362569584
Flag: com.android.bluetooth.flags.get_state_from_system_server
Test: atest ServiceBluetoothRoboTests
Change-Id: I016b5a147fbdc5d4667696616d504cbaf453b255