Try to use a known working ath docker image

I have found several builds failing due to selenium errors since yesterday, including the ATH itself and several internal builds.
I suspect something has happened with the docker image, maybe the firefox ECR version has change in the local repo or something similar

If I am right this version of the docker image should still work

essentials.yml

@@ -2,5 +2,6 @@
 ath:
   useLocalSnapshots: false
   athRevision: "06caf67d37d945ec5228a80d73714fac692c28d3"
+  athImage: "jenkins/ath:acceptance-test-harness-1.62"
   categories:
     - org.jenkinsci.test.acceptance.junit.SmokeTest