btif: Pass UIDs changed up to the Java layer

Previously we were simply responding with an INTERIM response and
leaving it at that.

Test: connect to BMW kit and check that interim is sent from Java
Bug: 62775732
Change-Id: Idb7de4417438f0c9697ee5c838b511cdd2223e80
(cherry picked from commit 3d7c99dc6db3f2a0392a0b273140eb03e0050ee5)