HH: Fix crash when calling JNI callback using main thread

btif_hh_connect() can be called through main thread and it lead to crash
with following message. "JNI DETECTED ERROR IN APPLICATION: a thread
xxxx is making JNI calls without being attached"
So we fix to switch callback to jni thread.

Bug: 243753956
Tag: #stability
Test: reconnect some mouse after BT turning on
Change-Id: Ib3576bca9026e7fdf164c972f2da22471005e01f