L2CAP: Dequeue next request if previous response is invalid

If we drop the invalid response packet without dequeuing next request,
the outgoing request queue will stuck. We should dequeue it as long as
the signalling id matches.

Also fix the scid/dcid mismatch in cert stack.

Test: cert/run_cert.sh. test_open_two_channels should be fixed.
Bug: 141557006
Change-Id: Id4dd9f279ece55aa5e78443c8027df91af1dd7c8