perf(backend): avoid N+1 selects from user table when packing many entities (#13911)

* perf(backend): avoid N+1 selects from `user` table when packing many entities

* perf(backend): use `packMany` instead of mapping to `pack`

packages/backend/src/server/api/endpoints/notes/reactions.ts

@@ -76,7 +76,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 
 			const reactions = await query.limit(ps.limit).getMany();
 
-			return await Promise.all(reactions.map(reaction => this.noteReactionEntityService.pack(reaction, me)));
+			return await this.noteReactionEntityService.packMany(reactions, me);
 		});
 	}
 }