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
(cherry picked from commit 5abb3b90f8490b1acaa8a1b634508fe61448e692)