fix: errors (#2496)

* fix: errors

* fix: err can be undefined

* tests: fix sticker tests

* fix: create channel require name

* fix: sticker helpers and tests

* tests: delete channel after tested guild stickers

rest/runMethod.ts

@@ -41,7 +41,7 @@ export async function runMethod<T = any>(
     if (!result.ok) {
       const err = await result.json().catch(() => {});
       // Legacy Handling to not break old code or when body is missing
-      if (!err.body) throw new Error(`Error: ${err.message ?? result.statusText}`);
+      if (!err?.body) throw new Error(`Error: ${err.message ?? result.statusText}`);
       throw rest.convertRestError(errorStack, err);
     }