Wait for a short time after starting the test actors

This is to fix some async scheduling issues in python 3.8 leading to
test failures.

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

tests/timeseries/mock_microgrid.py

@@ -80,7 +80,9 @@ async def start(self) -> Tuple[Sender[ComponentMetricRequest], ChannelRegistry]:
         """
         await self._server.start()
         await asyncio.sleep(0.1)
-        return await self._init_client_and_actors()
+        ret = await self._init_client_and_actors()
+        await asyncio.sleep(0.1)
+        return ret
 
     @classmethod
     async def new(