Exclude channel notes from featured polls (#13838)

* feat(backend): add `channelId` to `MiPoll` as a Denormalized field

* feat(backend): option to exclude polls in channels

* chore: exclude channel notes from featured polls

* docs(changelog): みつけるのアンケート欄にてチャンネルのアンケートが含まれてしまう問題を修正

* fix: missing license header

packages/backend/src/core/NoteCreateService.ts

@@ -473,6 +473,7 @@ export class NoteCreateService implements OnApplicationShutdown {
 						noteVisibility: insert.visibility,
 						userId: user.id,
 						userHost: user.host,
+						channelId: insert.channelId,
 					});
 
 					await transactionalEntityManager.insert(MiPoll, poll);