OPP: Add OPP 1.2 feature.

Add changes to support OPP 1.2 which uses OBEX over L2CAP.

Test: Connect with Remote OPP Client supporting OPP 1.2 and verify
that connection and transfer happens over L2CAP. Connect with Remote
OPP Client supporting OPP 1.1 and verify that connection and transfer
happens over RFCOMM.

Bug: 33010988
Change-Id: I44c2f2f01fb04f4306d0eb121d66dc08954966c0