fix: update MentionNode fallback to improve rendering

- Changed the fallback in MentionNode from displaying the mention name to null, enhancing the rendering behavior during loading states.

This update improves the user experience by ensuring a cleaner interface while mentions are being processed.

Signed-off-by: Innei <tukon479@gmail.com>

apps/desktop/layer/renderer/src/modules/ai-chat/editor/plugins/mention/MentionNode.tsx

@@ -103,7 +103,7 @@ export class MentionNode extends DecoratorNode<React.JSX.Element> {
 
   override decorate(_editor: LexicalEditor): React.JSX.Element {
     return (
-      <React.Suspense fallback={<span>@{this.__mentionData.name}</span>}>
+      <React.Suspense fallback={null}>
         <MentionComponent mentionData={this.__mentionData} />
       </React.Suspense>
     )