MLE-32962: Upgrade image pull is skipped for ARM images and inconsistently skipped for rootless images

[vitalykorolev]

Summary

Fixes two issues in the upgrade image handling logic: ARM image types were always skipping the upgrade image pull/test entirely instead of pulling the correct architecture-matched image, and the rootless skip condition was inconsistent across rootless variants. Also removes an upgrade test skip in Robot Framework keywords that is no longer needed now that ARM upgrade images are pulled correctly.

Root cause

pullUpgradeDockerImage() in the Jenkinsfile unconditionally skipped ARM image types, and its rootless skip check only matched the literal string "ubi-rootless" (missing "ubi9-rootless" and "ubi9-rootless-arm"), while also relying on a string comparison against params.DOCKER_TESTS instead of the resolved DOCKER_TESTS boolean.

Fix

Updated pullUpgradeDockerImage() to pull the matching ARM image type's latest-<majorVersion> tag instead of skipping, changed the rootless check to dockerImageType.contains("rootless") so it applies uniformly across all rootless variants, gated the skip on the DOCKER_TESTS boolean, and removed the now-unnecessary Skip If 'arm' in '${IMAGE_TYPE}' line from the Create upgrade container with keyword in test/keywords.resource.

Validation

• git diff --check: pass (no whitespace errors)
• Editor diagnostics on changed files: pass (none reported)
• make lint / structure-test / docker-tests: skipped locally (Docker daemon unavailable, limited connectivity); validated via manual Jenkins builds on the branch (multiple parameter combinations, all green): https://ml-clt-jenkins.progress.com/job/KubeNinjas/job/docker/job/Docker_CI/job/MLE-32962_fix-arm-rootless-upgrade-images/

[Copilot]

Copilot review overview

🟡 Changes recommended

A critical ARM platform mismatch remains in the upgrade-image pull path.

Review effort: Lite
Findings: 1

Open (1)

• Specify linux/arm64 when pulling ARM upgrade images · New

Resolved since last review (1)

• Avoid stale tagged images by always loading the archive