Rewrite a new hearing device pairing page with update UI for "See more
devices".
Bug: 307473972
Test: atest HearingDevicePairingFragmentTest
Test: flip the flag com.android.settings.flags.new_hearing_device_pairing_page && atest HearingAidPairingDialogFragmentTest AddDevicePreferenceControllerTest
Change-Id: Ic60601905e3d0d7d7c5b1ef9733652118a211f1d
