tests: Handle different delays in discovery_and_interface_disabled

tests: Handle different delays in discovery_and_interface_disabled

Test different delay intervals between the INTERFACE_DISABLED event
and the INTERFACE_ENABLED event for discovery_and_interface_disabled.

Previously, only a delay of 1 second was used, in which case the
scan results for the P2P_FIND operation were received after the
interface was enabled again, and the case the scan results were
received while the interface was disabled was not covered.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>