Fix after dis/reconnect HA, DUT will request to re-pair one side of HA

Root Cause: Another side of HA jumps to connecting state after pair-other-ear dialog appears.

Solution: Listen to onDeviceAttributesChanged() callback to know when
the sub device gets connected, then to dismiss dialog.

Bug: 236782832
Test: make RunSettingsRoboTests ROBOTEST_FILTER=HearingAidUtilsTest
Test: make RunSettingsRoboTests ROBOTEST_FILTER=HearingAidPairingDialogFragmentTest
Test: make RunSettingsRoboTests ROBOTEST_FILTER=AvailableMediaDeviceGroupControllerTest
Change-Id: I8dafefbb05e7cf1cadf37a7acbb2c5d66f2d0a78