Feat: Display MCP multiple selection bar #3221 (#8737)

### What problem does this PR solve?

Feat: Display MCP multiple selection bar #3221

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/agent/form/message-form/use-values.ts

@@ -1,18 +1,15 @@
 import { RAGFlowNodeType } from '@/interfaces/database/flow';
 import { isEmpty } from 'lodash';
 import { useMemo } from 'react';
+import { initialMessageValues } from '../../constant';
 import { convertToObjectArray } from '../../utils';
 
-const defaultValues = {
-  content: [],
-};
-
 export function useValues(node?: RAGFlowNodeType) {
   const values = useMemo(() => {
     const formData = node?.data?.form;
 
     if (isEmpty(formData)) {
-      return defaultValues;
+      return initialMessageValues;
     }
 
     return {