Fix crash prone code in BluetoothDeviceManager.

Bug: 237751446
Bug: 240215018
Test: BluetoothDeviceManagerTest
Merged-In: I722dded7744759f4485407d5f12e3a57d23b5fbf
Change-Id: I722dded7744759f4485407d5f12e3a57d23b5fbf
1 file changed