[github] Fix automerge github action issue when close&reopen PR. (sonic-net#14936)

When auto cherry pick PR is closed&reopen to rerun validation. post_cherry_pick action will be skipped.
Auto-merge scaning action will not merge that PR.

Author: liushilongbuaa

.github/workflows/automerge_scan.yml

@@ -47,6 +47,7 @@ jobs:
             # Others success flag:   conclusion in SUCCESS,NEUTRAL
             # Ignore Azure.sonic-mgmt stage check result. It may be set continueOnError
             echo "$name" | grep "Azure.sonic-mgmt (" && continue
+            echo "$name" | grep "cherry_pick" && continue
             # rerun Azure.sonic-mgmt per day
             if [[ "$name" == "Azure.sonic-mgmt" ]] && [[ "$conclusion" == "FAILURE" ]];then
               completedAt=$(echo $check | jq -r '.completedAt')