test: Remove ZooKeeper 3.9.3 (#784)

Author: NickLarsenNZ

tests/test-definition.yaml

@@ -25,7 +25,6 @@ dimensions:
       # - 30.0.0,oci.stackable.tech/sdp/druid:30.0.0-stackable0.0.0-dev
   - name: zookeeper
     values:
-      - 3.9.3
       - 3.9.4
   - name: zookeeper-latest
     values: