[HA Status] Implement hearing devices connection status listener

* Add listener and notify mechanism in HearingAidDeviceManager
* Register listener in accessibility floating menu
* Oserve hearing device connection status and hearing device target position in MenuView

Bug: 357882387
Test: atest HearingAidDeviceManagerTest MenuInfoRepositoryTest
Flag: com.android.settingslib.flags.hearing_device_set_connection_status_report
Change-Id: I34809c8744f62ca766b634db9156477097aa1145