Merge "Expose service changed event to application (3/3)" am: e8e83ee0b2 am: 49f2c14f89 am: d8a7fd57c2

Original change: https://android-review.googlesource.com/c/platform/packages/apps/Bluetooth/+/1433964

Change-Id: If52752f3f33584d86883464e452d653f1b0ad228