refactor(api/core/workflow/workflow_engine_manager.py): Remove (#6630)

Signed-off-by: -LAN- <laipz8200@outlook.com>

api/core/workflow/workflow_engine_manager.py

@@ -87,15 +87,18 @@ class WorkflowEngineManager:
 
         return default_config
 
-    def run_workflow(self, *, workflow: Workflow,
+    def run_workflow(
+        self,
+        *,
+        workflow: Workflow,
         user_id: str,
         user_from: UserFrom,
         invoke_from: InvokeFrom,
         user_inputs: Mapping[str, Any],
         system_inputs: Mapping[SystemVariable, Any],
         callbacks: Sequence[WorkflowCallback],
-                     call_depth: int = 0,
-                     variable_pool: Optional[VariablePool] = None) -> None:
+        call_depth: int = 0
+    ) -> None:
         """
         :param workflow: Workflow instance
         :param user_id: user id
@@ -120,7 +123,6 @@ class WorkflowEngineManager:
             raise ValueError('edges in workflow graph must be a list')
 
         # init variable pool
-        if not variable_pool:
         variable_pool = VariablePool(
             system_variables=system_inputs,
             user_inputs=user_inputs,