pr-check: Don't dupe locked comment

.github/workflows/pr-check.yml

@@ -295,6 +295,7 @@ jobs:
 
             if label_exists_any "pr-check-blocked" "blocked" \
               && ! comment_exists_any "$BUILD_SUCCESS_COMMENT" \
+              && ! comment_exists_any "$LOCKED_COMMENT_PARTIAL" \
               && [ "$(echo "$PR_COMMENTS" | grep -E -c 'Test build.*failed')" -gt 5 ]; then
                 echo "PR is blocked and too many failing builds. Locking"
                 gh pr comment "$PR_NUM" --body "$LOCKED_COMMENT" >/dev/null 2>&1 || true
@@ -343,5 +344,6 @@ jobs:
             This pull request is marked as blocked and has too many
             builds failing. Please build it locally following the
             instructions and push the relevant changes first.
+          LOCKED_COMMENT_PARTIAL: "has too many builds failing"
           REVIEW_COMMENT_PARTIAL: "This pull request is temporarily marked as blocked as some"
           DOMAIN_COMMENT_PARTIAL: "The domain to be used for verification is"