Create Pairing Test infrastructure with discovery support

- Implemented Pairing Test infrastructure for test cases to perform device discovery.
- Add BT pairing test for LE bonding with Auto transport when a dual mode remote device is discoverable only over LE transport.

Test: atest PairingWithDiscoveryTest
Flag: TEST_ONLY
Bug: 399243061
Change-Id: I8ec377d98f102f58139849480d1dd89adf3d412f