daemon: properly go through the data collect state for grpc session shutdown, also check and avoid repeating data collect or shutdown when already past those states

daemon/core/api/grpc/server.py

@@ -315,6 +315,7 @@ class CoreGrpcServer(core_pb2_grpc.CoreApiServicer):
         """
         logging.debug("stop session: %s", request)
         session = self.get_session(request.session_id, context)
+        session.data_collect()
         session.shutdown()
         return core_pb2.StopSessionResponse(result=True)