[CI] SmokeTestWatcherWithSecurityIT.testSearchInputHasPermissions fails

[andrershov]

See this build
https://elasticsearch-ci.elastic.co/job/elastic+elasticsearch+6.x+multijob-unix-compatibility/os=centos/58/console

There are 2 test failures, but the reasons seem to be different. testSearchInputHasPermissions fails with 503 HTTP response. Unable to reproduce locally.

REPRODUCE WITH: ./gradlew :x-pack:qa:smoke-test-watcher-with-security:integTestRunner \
  -Dtests.seed=484163AFA937AD5E \
  -Dtests.class=org.elasticsearch.smoketest.SmokeTestWatcherWithSecurityIT \
  -Dtests.method="testSearchInputHasPermissions" \
  -Dtests.security.manager=true \
  -Dtests.locale=it \
  -Dtests.timezone=Antarctica/Mawson \
  -Dcompiler.java=11 \
  -Druntime.java=8

Probably related to #33320

[elasticmachine]

Pinging @elastic/es-core-infra