[ci] Remove unused jobs (#2502)

<del>PR custom review is deprecated. Now `review-bot` performs these
functions.</del>
PR removes unused ci jobs and adjusts zombienet jobs for merge queues

cc @Bullrich

.gitlab/pipeline/zombienet/substrate.yml

@@ -6,6 +6,9 @@
   before_script:
     # Exit if the job is not merge queue
     # - if [[ $CI_COMMIT_REF_NAME != *"gh-readonly-queue"* ]]; then echo "I will run only in a merge queue"; exit 0; fi
+    # Docker images have different tag in merge queues
+    - if [[ $CI_COMMIT_REF_NAME == *"gh-readonly-queue"* ]]; then export DOCKER_IMAGES_VERSION="${CI_COMMIT_SHORT_SHA}"; fi
+    - export SUBSTRATE_IMAGE_TAG=${DOCKER_IMAGES_VERSION}
     - echo "Zombienet Tests Config"
     - echo "${ZOMBIENET_IMAGE}"
     - echo "${GH_DIR}"
@@ -21,7 +24,7 @@
     - .kubernetes-env
     - .zombienet-refs
   variables:
-    SUBSTRATE_IMAGE_TAG: ${DOCKER_IMAGES_VERSION}
+    # SUBSTRATE_IMAGE_TAG: ${DOCKER_IMAGES_VERSION}
     SUBSTRATE_IMAGE: "docker.io/paritypr/substrate"
     GH_DIR: "https://github.com/paritytech/substrate/tree/${CI_COMMIT_SHA}/zombienet"
     LOCAL_DIR: "/builds/parity/mirrors/polkadot-sdk/substrate/zombienet"