message: [cti] Add --validator-tag
  This command allows to override validator tag(similar to how to --cluster-test-tag allows to override validator tag).
  Use case here is running cti with --pr and have it new cluster test image, but pick up some different(existing) validator image as a base
  Closes:
  Approved by: snakech
diff: @@ -6,11 +6,11 @@ set -o pipefail
  TAG=""
  CLUSTER_TEST_TAG=""
  +VALIDATOR_TAG=""
  PR=""
  WORKSPACE=""
  ENV=""
  REPORT=""
  -DEPLOY=yes
  EXIT_CODE=0
  K8S_CONTEXT_PATTERN='arn:aws:eks:us-west-2:853397791086:cluster/CLUSTERNAME-k8s-testnet'
  @@ -151,6 +151,10 @@ while (( "$#" )); do
  CLUSTER_TEST_TAG=$2
  shift 2
  ;;
  + --validator-tag)
  + VALIDATOR_TAG=$2
  + shift 2
  + ;;
  -W|--workspace)
  WORKSPACE=$2
  shift 2
  @@ -199,6 +203,7 @@ if [ -z "$TAG" ]; then
  fi
  CLUSTER_TEST_TAG=${CLUSTER_TEST_TAG:-${TAG}}
  +VALIDATOR_TAG=${VALIDATOR_TAG:-${TAG}}
  OUTPUT_TEE=${CTI_OUTPUT_LOG:-$(mktemp)}
  @@ -217,7 +222,7 @@ ENV="$ENV AWS_ROLE_SESSION_NAME=AWS_ROLE_SESSION_NAME"
  join_env_vars $ENV
  DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
  sed -e "s/{pod_name}/${pod_name}/g" \
  - -e "s/{image_tag}/${TAG}/g" \
  + -e "s/{image_tag}/${VALIDATOR_TAG}/g" \
  -e "s/{cluster_test_image_tag}/${CLUSTER_TEST_TAG}/g" \
  -e "s^{env_variables}^${retval_join_env_vars}^g" \
  -e "s+{extra_args}+${retval_join_args}+g" \
  