Added success response (#3928)

Author: Laskewitz

custom-connectors/MCP-Streamable-HTTP/apiDefinition.swagger.json

@@ -15,10 +15,14 @@
       "post": {
         "summary": "MCP Server Streamable HTTP",
         "x-ms-agentic-protocol": "mcp-streamable-1.0",
-        "operationId": "InvokeServer",
-        "responses": { }
-      }
+        "operationId": "InvokeMCP",
+        "responses": {
+          "200": {
+            "description": "Success"
+          }
+        }
+      },
+      "securityDefinitions": {}
     }
-  },
-  "securityDefinitions": { }
+  }
 }