update build system test to run on main (#5664)

Author: esauerbo

.github/workflows/build-system-test-react-native.yml

@@ -6,6 +6,8 @@ permissions:
   id-token: write # This is required for aws-actions/configure-aws-credentials
 
 on:
+  push:
+    branches: ['main']
   schedule:
     - cron: '0 */2 * * *' # Run on the first minute of each even numbered hour