[action] Update AutoMergeScan action to ignore Semgrep and rerun fail…

…ed job. (sonic-net#14118)

Why I did it
Semgrep check has some issues. Ignore it.
check automerge label.
Ignore Azure.sonic-buildimage sub test jobs. Only check final result.
How I did it

.github/workflows/automerge_scan.yml

@@ -30,6 +30,9 @@ jobs:
  echo PR: $(($i+1))/$count, URL: $url, createdAt: $created_at, now: $(date -u +"%FT%TZ")
  [[ "$url" == "" ]] && continue
  [[ $created_at > $(date --date "1 hour ago" -u +"%FT%TZ") ]] && continue
+ # only check automerge PR.
+ cat prs.log | jq -r ".[$i].labels[].name" | grep automerge || continue
+
  checks=$(cat prs.log | jq ".[$i].statusCheckRollup")
  checks_count=$(echo $checks | jq 'length')
  echo Checks count: $checks_count
@@ -38,9 +41,14 @@ jobs:
  check=$(echo $checks | jq ".[$j]")
  state=$(echo $check | jq -r '.state')
  conclusion=$(echo $check | jq -r '.conclusion')
+ name=$(echo $check | jq -r '.name')
 
  # EasyCLA success flag: state=SUCCESS
  # Others success flag: conclusion in SUCCESS,NEUTRAL
+ # Ignore Azure.sonic-buildimage stage check result. It may be set continueOnError
+ echo "$name" | grep "Azure.sonic-buildimage (" && continue
+ # Ignore Semgrep, it has issues.
+ [[ "$name" == "Semgrep" ]] && continue
  if [[ "$state" == "SUCCESS" ]];then
  # check pass
  continue