Bluetooth: Unpair both earbuds on unpair.

1> On unpair initiation to primary, Initiate Unpair
   for peer secondary TWS device as well.
2> On pairing to primary earbud, Initiate connection to second
   earbud.

CRs-fixed: 2230362
Change-Id: I0d0e7c3bc66d4ff24a2b767996bc1367022901d6