fix(backend): correct `app`-type notification schema (#14471)

packages/backend/src/models/Notification.ts

@@ -85,7 +85,7 @@ export type MiNotification = {
 	/**
 	 * アプリ通知のbody
 	 */
-	customBody: string | null;
+	customBody: string;
 
 	/**
 	 * アプリ通知のheader

packages/backend/src/models/json-schema/notification.ts

@@ -311,11 +311,11 @@ export const packedNotificationSchema = {
 			},
 			header: {
 				type: 'string',
-				optional: false, nullable: false,
+				optional: false, nullable: true,
 			},
 			icon: {
 				type: 'string',
-				optional: false, nullable: false,
+				optional: false, nullable: true,
 			},
 		},
 	}, {

packages/misskey-js/src/autogen/types.ts

@@ -4253,7 +4253,7 @@ export type components = {
       /** @enum {string} */
       type: 'achievementEarned';
       achievement: string;
-    } | {
+    } | ({
       /** Format: id */
       id: string;
       /** Format: date-time */
@@ -4261,9 +4261,9 @@ export type components = {
       /** @enum {string} */
       type: 'app';
       body: string;
-      header: string;
-      icon: string;
-    } | {
+      header: string | null;
+      icon: string | null;
+    }) | {
       /** Format: id */
       id: string;
       /** Format: date-time */