Replaces HearingDevicePairingDetail with HearingDevicePairingFragment

The new pairing page includes new UI for "See more devices" buttton and
can show MFi + ASHA devices in the pairing list while these devices only
advertise MFi HAS uuid in pairing mode.

As allowed by "Flag Cleanup Policy", this change finishes the rollout of trunkfood flag new_hearing_device_pairing_page by defaulting to the "true" state.

Bug: 307473972
Test: atest HearingAidPairingDialogFragmentTest
Test: atest AddDevicePreferenceControllerTest
Change-Id: I6c3377d535139d62791548557c581317d1878e9d