CI: separate Aiter Test concurrency for push and schedule (ROCm#2718)

Split main-branch concurrency by event type so scheduled runs do not block push-triggered validation when a long queued job keeps the nightly workflow open.

Author: gyohuangxin

.github/workflows/aiter-test.yaml

@@ -17,7 +17,8 @@ on:
     - cron: '0 22 * * *'  # 6:00 AM Beijing Time (UTC+8)
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
+  # Keep scheduled main runs from blocking push-triggered validation.
+  group: ${{ github.workflow }}-${{ github.ref }}-${{ github.event_name }}
   cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
 
 env: