Greatly reduce repeated code

functions/api/game-appeals/[id]/deny.ts

@@ -1,15 +1,11 @@
+import { jsonError } from "../../../common.js";
+
 export async function onRequestPost(context: RequestContext) {
   const appealId = context.params.id as string;
 
   const appeal = await context.env.DATA.get(`gameappeal_${appealId}`);
 
-  if (!appeal)
-    return new Response('{"error":"Appeal not found"}', {
-      headers: {
-        "content-type": "application/json",
-      },
-      status: 404,
-    });
+  if (!appeal) return jsonError("Appeal not found", 404);
 
   const appealData = JSON.parse(appeal);