server: use AbortSignal.timeout

Using AbortSignal.timeout is a cleaner solution that using an
AbortController and triggering it ourselves with setTimeout.

packages/backend/src/misc/fetch.ts

@@ -49,11 +49,6 @@ export async function getResponse(_args: {
 		..._args,
 	};
 
-	const controller = new AbortController();
-	setTimeout(() => {
-		controller.abort();
-	}, args.timeout);
-
 	const res = await fetch(args.url, {
 		method: args.method,
 		headers: Object.assign({
@@ -63,7 +58,7 @@ export async function getResponse(_args: {
 		redirect: args.redirect,
 		size: args.size,
 		agent: getAgentByUrl,
-		signal: controller.signal,
+		signal: AbortSignal.timeout(args.timeout),
 	});
 
 	if (