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

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

Change-Id: I7fcd2c91384546b87a01e536470e709381aa6e19