fix: add sleep to test amm-arb

hummingbot/strategy/amm_arb/amm_arb.py

@@ -337,6 +337,7 @@ async def execute_arb_proposals(self, arb_proposals: List[ArbProposal]):
                 })
 
                 if not self._concurrent_orders_submission:
+                    await asyncio.sleep(6)
                     await arb_side.completed_event.wait()
                     if arb_side.is_failed:
                         self.log_with_clock(logging.ERROR,