chore: use default timeout for AMO

...because increasing it didn't help, their server is broken

scripts/amo-sign.js

@@ -17,7 +17,6 @@ async function main() {
     channel: 'unlisted',
     downloadDir: process.env.ASSETS_DIR,
     id: manifest.browser_specific_settings.gecko.id,
-    timeout: 30 * 60e3, // 30 minutes
   });
   if (!result.success) {
     console.error(result);