Hearing Aid: Keep configuration after disconnect()

After disconnect(), the Hearing Aid service removes the device from the
white list, but retains the configuration. The Java Hearing Aid service
still knows the hiSyncId and capabilities, so it can connect() to
multiple devices at the same time

Bug: 69623109
Test: manual and unit test for Java service
Change-Id: Ic17b9be7e6a0577baecd520680abffbaf0a0dc47