Fix: Clicking on the empty dialog box on the agent exploration page will result in an error. (#14198)

### What problem does this PR solve?

Fix: Clicking on the empty dialog box on the agent exploration page will
result in an error.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

web/src/pages/agent/explore/components/session-list.tsx

@@ -13,7 +13,7 @@ interface SessionListProps {
 }
 
 export function SessionList({
-  selectedSessionId,
+  selectedSessionId = '',
   onSelectSession,
 }: SessionListProps) {
   const { t } = useTranslation();

web/src/pages/agent/explore/hooks/use-select-derived-session-list.ts

@@ -1,6 +1,5 @@
 import { useFetchSessionsByCanvasId } from '@/hooks/use-agent-request';
 import { IAgentLogResponse } from '@/interfaces/database/agent';
-import { generateConversationId } from '@/utils/chat';
 import { useCallback, useEffect, useState } from 'react';
 import { useExploreUrlParams } from './use-explore-url-params';
 
@@ -14,11 +13,10 @@ export const useSelectDerivedSessionList = () => {
   const { setSessionId } = useExploreUrlParams();
 
   const addTemporarySession = useCallback(() => {
-    const sessionId = generateConversationId();
     const now = Date.now() / 1000;
 
     const tempSession: IAgentLogResponse & { is_new?: boolean } = {
-      id: sessionId,
+      id: '',
       message: [],
       create_date: '',
       create_time: now,