CCM-8585: use sed

Author: alexnuttall

.github/actions/normalize-branch-name/action.yaml

@@ -11,9 +11,7 @@ runs:
       run: |
         branch=$(git rev-parse --abbrev-ref HEAD)
         stripped=$(echo $branch | sed -e 's/[^a-zA-Z0-9-]//g' | tr '[:upper:]' '[:lower:]')
-        echo $stripped
-        starting_from_jira_ref=$(echo $stripped | grep -Eo '\d{4,}.*' || true)
-        echo $starting_from_jira_ref
+        starting_from_jira_ref=$(echo $stripped | sed -n 's/.*\([0-9]\{4,\}.*\)$/\1/p')
         with_fallback=${starting_from_jira_ref:-$stripped}
         chopped=$(echo $with_fallback | head -c 15)
         echo "normalized_branch_name=$chopped" >> $GITHUB_OUTPUT