fix(backend) api/iの未読のお知らせにcreatedAtを追加するように修正 (#12092)

Co-authored-by: sorairo <sorairo@shiosyakeyakini.info>

packages/backend/src/core/entities/UserEntityService.ts

@@ -322,7 +322,11 @@ export class UserEntityService implements OnModuleInit {
 
 		const isModerator = isMe && opts.detail ? this.roleService.isModerator(user) : null;
 		const isAdmin = isMe && opts.detail ? this.roleService.isAdministrator(user) : null;
-		const unreadAnnouncements = isMe && opts.detail ? await this.announcementService.getUnreadAnnouncements(user) : null;
+		const unreadAnnouncements = isMe && opts.detail ?
+			(await this.announcementService.getUnreadAnnouncements(user)).map((announcement) => ({
+				createdAt: this.idService.parse(announcement.id).date.toISOString(),
+				...announcement,
+			})) : null;
 
 		const falsy = opts.detail ? false : undefined;