fix: incorrect workflow max call depth (#4759)

api/core/workflow/nodes/tool/tool_node.py

@@ -61,7 +61,7 @@ class ToolNode(BaseNode):
                 user_id=self.user_id,
                 workflow_id=self.workflow_id, 
                 workflow_tool_callback=DifyWorkflowCallbackHandler(),
-                workflow_call_depth=self.workflow_call_depth + 1
+                workflow_call_depth=self.workflow_call_depth,
             )
         except Exception as e:
             return NodeRunResult(