Test Old Arch with Maestro (#48244)

Summary:
This pr tests the Old Arch on the Template app using Maestro

## Changelog:
[Internal] - Test old arch in CI with Maestro for template app

Pull Request resolved: https://github.com/facebook/react-native/pull/48244

Test Plan: GHA

Reviewed By: cortinico

Differential Revision: D67141524

Pulled By: cipolleschi

fbshipit-source-id: bef3a9b6fec9d7c91d858d534a2d00e91f1842b5

.github/workflow-scripts/maestro-android.js

@@ -55,6 +55,7 @@ async function main() {
       stdio: 'ignore',
       detached: true,
     });
+    metroProcess.unref();
     console.info(`- Metro PID: ${metroProcess.pid}`);
   }
 
@@ -88,15 +89,15 @@ async function main() {
     if (IS_DEBUG && metroProcess != null) {
       const pid = metroProcess.pid;
       console.info(`Kill Metro. PID: ${pid}`);
-      process.kill(-pid);
+      process.kill(pid);
       console.info(`Metro Killed`);
-      process.exit();
     }
   }
 
   if (error) {
     throw error;
   }
+  process.exit();
 }
 
 function sleep(ms) {