fix(nrdot-haproxy): use exit 31 for service failed to start

Use newrelic-cli standard exit code 31 instead of generic exit 1
when nrdot-collector fails to start. This allows the CLI to properly
categorize the failure, matching the pattern used by nginx and
elasticsearch-otel recipes.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: gmanandhar-nr

recipes/newrelic/infrastructure/nrdot/haproxy/debian.yml

@@ -391,4 +391,5 @@ install:
           done
           echo "nrdot-collector failed to start within ${MAX_RETRIES} attempts." >&2
           journalctl -u nrdot-collector.service --no-pager -n 20
-          exit 1
+          # Exit 31: newrelic-cli standard code for service failed to start.
+          exit 31

recipes/newrelic/infrastructure/nrdot/haproxy/rhel.yml

@@ -396,5 +396,6 @@ install:
           done
           echo "nrdot-collector failed to start within ${MAX_RETRIES} attempts." >&2
           journalctl -u nrdot-collector.service --no-pager -n 20
-          exit 1
+          # Exit 31: newrelic-cli standard code for service failed to start.
+          exit 31