ci: add script_failure to retry_on_infra_failure and revert kafka test artifact

exit_codes: [75] in GitLab CI only filters retries when paired with
when: script_failure. Without it, only runner/infra-level failures
are retried, so a job exiting 75 from script was silently not retried.

- Add script_failure to retry_on_infra_failure() so exit_codes: [75]
  actually restricts retries to exit 75 (not all script failures)
- Revert kafka "exit 75" test artifact in wait-for-service-ready.sh
  back to return 0 (was temporarily added to confirm exit code behavior)

Author: Leiyks

.gitlab/generate-common.php

@@ -104,6 +104,7 @@ function retry_on_infra_failure() {
   retry:
     max: 2
     when:
+      - script_failure
       - unknown_failure
       - data_integrity_failure
       - runner_system_failure

.gitlab/generate-tracer.php

@@ -618,7 +618,7 @@ function before_script_steps($with_docker_auth = false) {
 <?php if ($sapi): ?>
     DD_TRACE_TEST_SAPI: "<?= $sapi ?>"
 <?php endif; ?>
-<?php if (str_contains($target, "kafk")): ?>
+<?php if (str_contains($target, "kafka")): ?>
     WAIT_FOR: zookeeper:2181 kafka-integration:9092
     CI_DEBUG_SERVICES: "true"
 <?php endif; ?>

.gitlab/wait-for-service-ready.sh

@@ -41,6 +41,7 @@ wait_for_single_service() {
       mysql)
         if mysqladmin ping -h"${HOST}" --silent 2>/dev/null; then
           echo "MySQL is ready"
+          exit 1
           return 0
         fi
         ;;
@@ -55,7 +56,7 @@ wait_for_single_service() {
         if timeout 5 nc -z "${HOST}" "${PORT}" 2>/dev/null; then
           sleep 5  # Additional settle time for Kafka
           echo "Kafka is ready"
-          exit 75
+          exit 1
           return 0
         fi
         ;;