通知設定が開けないのを修正

packages/frontend/src/components/MkPushNotificationAllowButton.vue

@@ -141,6 +141,9 @@ function encode(buffer: ArrayBuffer | null) {
 	return outputArray;
 }
 
+if (navigator.serviceWorker == null) {
+	// TODO: よしなに？
+} else {
 	navigator.serviceWorker.ready.then(async swr => {
 		registration = swr;
 
@@ -160,6 +163,7 @@ navigator.serviceWorker.ready.then(async swr => {
 			}
 		}
 	});
+}
 
 defineExpose({
 	pushRegistrationInServer: $$(pushRegistrationInServer),