fix(backend): apOrHtml Constraintが正しく評価されない問題を修正 (#15213)

* fix(backend/ActivityPubServerService): apOrHtml Constraintが正しく評価されない問題を修正 (MisskeyIO#869)

* Update Changelog

* indent

---------

Co-authored-by: あわわわとーにゅ <17376330+u1-liquid@users.noreply.github.com>

packages/backend/src/server/ActivityPubServerService.ts

@@ -519,8 +519,8 @@ export class ActivityPubServerService {
 			},
 			deriveConstraint(request: IncomingMessage) {
 				const accepted = accepts(request).type(['html', ACTIVITY_JSON, LD_JSON]);
-				const isAp = typeof accepted === 'string' && !accepted.match(/html/);
-				return isAp ? 'ap' : 'html';
+				if (accepted === false) return null;
+				return accepted !== 'html' ? 'ap' : 'html';
 			},
 		});