feat: refactor MCP tool execution to improve parameter handling

Author: liuruibin

apps/application/flow/step_node/mcp_node/impl/base_mcp_node.py

@@ -28,7 +28,7 @@ async def call_tool(s, t, a):
 
         res = asyncio.run(call_tool(servers, mcp_tool, arguments))
         print(res)
-        return NodeResult({'result': res.content}, {})
+        return NodeResult({'result': res.content[0].text}, {})
 
     def get_reference_content(self, fields: List[str]):
         return str(self.workflow_manage.get_reference_field(