Don't invoke search complete when cancelling remote name request

Remote Name Request Cancel command will always generate Remote Name
Request Complete event. Because we also will invoke search complete for
the event, we shouldn't invoke it as well for the command, otherwise we
will double-invoke search complete.

Both invocations will set the discovery_state to Stopped, so one issue
that might happen is if the above layer starts discovery procedure
between the two invocations. If this happens, the discovery is started,
but the above layer will get "discovery_state = Stopped" from the
second invocation.

Bug: 318315420
Bug: 321170442
Test: m -j
Test: Open the pairing window. Right when RNR is ongoing, start a
      bonding procedure with a device that will reject it.
      Verify discovery procedure continues and discovery_state is
      Started, and we can immediately bond with another device.
Tag: #floss

Change-Id: I21afece04292e9cd92666e2cfd809f0263dca19e