Include Headtracker service in the list of interesting services

btif_dm reports only the "interesting" services after pairing.

Test: mmm packages/modules/Bluetooth
Flag: com.android.bluetooth.flags.android_headtracker_service
Bug: 332590397
Bug: 335708774
Change-Id: I366d098949a082d0e917f5a2e982c78ebce93a2d