Check-out the target commit when preparing PROD build artifacts (#38678)

We have now a separate job that prepares and uploads artifacts
when PROD image is being prepared for K8S testing. This saves a bit
of time to prepare PROD image. However this step had a bug - it
checked out the `main` version of code when preparing airflow and
provider packages, so it was really testing the "previous" merge
not the "current" PR.

This PR switches the job to prepare artifacts to use the same
checkout strategy as the other build-image workflow jobs.

.github/workflows/prod-image-build.yml

@@ -127,11 +127,54 @@ jobs:
         shell: bash
         run: docker run -v "${GITHUB_WORKSPACE}:/workspace" -u 0:0 bash -c "rm -rf /workspace/*"
         if: inputs.do-build == 'true' && inputs.upload-package-artifact == 'true'
-      - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
-        uses: actions/checkout@v4
+      - uses: actions/checkout@v4
         with:
+          ref: ${{ inputs.target-commit-sha }}
           persist-credentials: false
         if: inputs.do-build == 'true' && inputs.upload-package-artifact == 'true'
+      ####################################################################################################
+      #  BE VERY CAREFUL HERE! THIS LINE AND THE END OF THE WARNING. IN PULL REQUEST TARGET WORKFLOW
+      #  WE CHECK OUT THE TARGET COMMIT ABOVE TO BE ABLE TO BUILD THE IMAGE FROM SOURCES FROM THE
+      #  INCOMING PR, RATHER THAN FROM TARGET BRANCH. THIS IS A SECURITY RISK, BECAUSE THE PR
+      #  CAN CONTAIN ANY CODE AND WE EXECUTE IT HERE. THEREFORE, WE NEED TO BE VERY CAREFUL WHAT WE
+      #  DO HERE. WE SHOULD NOT EXECUTE ANY CODE THAT COMES FROM THE PR. WE SHOULD NOT RUN ANY BREEZE
+      #  COMMAND NOR SCRIPTS NOR COMPOSITE ACTIONS. WE SHOULD ONLY RUN CODE THAT IS EMBEDDED DIRECTLY IN
+      #  THIS WORKFLOW - BECAUSE THIS IS THE ONLY CODE THAT WE CAN TRUST.
+      ####################################################################################################
+      - name: Checkout target branch to 'target-airflow' folder to use ci/scripts and breeze from there.
+        uses: actions/checkout@v4
+        with:
+          path: "target-airflow"
+          ref: ${{ github.base_ref }}
+          persist-credentials: false
+        if: >
+          inputs.do-build == 'true' && inputs.pull-request-target == 'true' &&
+          inputs.is-committer-build != 'true' && inputs.upload-package-artifact == 'true'
+      - name: >
+          Replace "scripts/ci", "dev", ".github/actions" and ".github/workflows" with the target branch
+          so that the those directories are not coming from the PR
+        shell: bash
+        run: |
+          echo
+          echo -e "\033[33m Replace scripts, dev, actions with target branch for non-committer builds!\033[0m"
+          echo
+          rm -rfv "scripts/ci"
+          rm -rfv "dev"
+          rm -rfv ".github/actions"
+          rm -rfv ".github/workflows"
+          mv -v "target-airflow/scripts/ci" "scripts"
+          mv -v "target-airflow/dev" "."
+          mv -v "target-airflow/.github/actions" "target-airflow/.github/workflows" ".github"
+        if: >
+          inputs.do-build == 'true' && inputs.pull-request-target == 'true' &&
+          inputs.is-committer-build != 'true'
+      ####################################################################################################
+      #  HERE IT'S A BIT SAFER. THE `dev`, `scripts/ci` AND `.github/actions` ARE NOW COMING FROM THE
+      #  BASE_REF - WHICH IS THE TARGET BRANCH OF THE PR. WE CAN TRUST THAT THOSE SCRIPTS ARE SAVE TO RUN.
+      #  ALL THE REST OF THE CODE COMES FROM THE PR, AND FOR EXAMPLE THE CODE IN THE `Dockerfile.ci` CAN
+      #  BE RUN SAFELY AS PART OF DOCKER BUILD. BECAUSE IT RUNS INSIDE THE DOCKER CONTAINER AND IT IS
+      #  ISOLATED FROM THE RUNNER.
+      ####################################################################################################
       - name: "Cleanup docker"
         run: ./scripts/ci/cleanup_docker.sh
         if: inputs.do-build == 'true' && inputs.upload-package-artifact == 'true'