Merge "Reuse BluetoothPan object and use it under tethering handler thread" am: 5c4010e196 am: b823c10754 am: ba1285c1d1 am: 1290047da0

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1908683

Change-Id: If3110c5b9bb05f1fe415934b3b1da5254a5742f7