Greatly reduce repeated code

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

@@ -1,3 +1,5 @@
+import { jsonError } from "../../../common.js";
+
 export async function onRequestPost(context: RequestContext) {
   const { appeal } = context.data;
   const body = new FormData();
@@ -20,12 +22,7 @@ export async function onRequestPost(context: RequestContext) {
 
   if (!emailReq.ok) {
     console.log(await emailReq.json());
-    return new Response('{"error":"Failed to deny appeal"}', {
-      headers: {
-        "content-type": "application/json",
-      },
-      status: 500,
-    });
+    return jsonError("Failed to deny appeal", 500);
   }
 
   await context.env.D1.prepare("UPDATE appeals SET open = 0 WHERE id = ?;")