Fix: Click the reset button on the agent page shared externally, and the greeting in conversation mode should not be deleted. #10567 (#10571)

### What problem does this PR solve?

Fix: Click the reset button on the agent page shared externally, and the
greeting in conversation mode should not be deleted. #10567
### Type of change

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

web/src/pages/agent/hooks/use-get-begin-query.tsx

@@ -27,13 +27,16 @@ export function useSelectBeginNodeDataInputs() {
   );
 }
 
-export function useIsTaskMode() {
+export function useIsTaskMode(isTask?: boolean) {
   const getNode = useGraphStore((state) => state.getNode);
 
   return useMemo(() => {
+    if (typeof isTask === 'boolean') {
+      return isTask;
+    }
     const node = getNode(BeginId);
     return node?.data?.form?.mode === AgentDialogueMode.Task;
-  }, [getNode]);
+  }, [getNode, isTask]);
 }
 
 export const useGetBeginNodeDataQuery = () => {

web/src/pages/agent/hooks/use-send-shared-message.ts

@@ -59,6 +59,7 @@ export const useSendNextSharedMessage = (
     addEventList,
     beginParams: params,
     isShared: true,
+    isTaskMode,
   });
 
   const ok = useCallback(