BumbleBluetoothTests: Introduce a PandoraDevice junit Rule

This manages the lifecycle of the PandoraDevice to factor
some boilerplate used in each test.

This also has the advantage of not running the after function if
the before one threw an Exception.

Bug: 266884665
Test: atest BumbleBluetoothTests
Change-Id: I69d0d9ed7482083ee1008ecb90fbee548e3774b6