feat(server): Nullable asset dates (#15669)

* nullable dates

* wip

* don't search for null dates

* Add placeholder type

* cleanup

server/src/repositories/activity.repository.ts

@@ -65,6 +65,9 @@ export class ActivityRepository {
       .where('activity.albumId', '=', albumId)
       .where('activity.isLiked', '=', false)
       .where('assets.deletedAt', 'is', null)
+      .where('assets.fileCreatedAt', 'is not', null)
+      .where('assets.fileModifiedAt', 'is not', null)
+      .where('assets.localDateTime', 'is not', null)
       .executeTakeFirstOrThrow();
 
     return count as number;