feat(backend): Webhook設定でsecretを空に出来るように (#11784)

* feat(backend): allow webhook secret to be empty

* Update CHANGELOG.md

packages/backend/src/server/api/endpoints/i/webhooks/create.ts

@@ -34,12 +34,12 @@ export const paramDef = {
 	properties: {
 		name: { type: 'string', minLength: 1, maxLength: 100 },
 		url: { type: 'string', minLength: 1, maxLength: 1024 },
-		secret: { type: 'string', minLength: 1, maxLength: 1024 },
+		secret: { type: 'string', maxLength: 1024, default: '' },
 		on: { type: 'array', items: {
 			type: 'string', enum: webhookEventTypes,
 		} },
 	},
-	required: ['name', 'url', 'secret', 'on'],
+	required: ['name', 'url', 'on'],
 } as const;
 
 // TODO: ロジックをサービスに切り出す