feat: add TikTok embed support

src/app/components/message/content/index.ts

@@ -1,6 +1,7 @@
 export * from './ThumbnailContent';
 export * from './ImageContent';
 export * from './VideoContent';
+export * from './VideoFrameThumbnail';
 export * from './AudioContent';
 export * from './FileContent';
 export * from './FallbackContent';