Add docker-cli, fix apt sources, and keep apt lists

[mitesch]

Description

Fixes:
#13464
#13426

Related issue:

Check list

• Related issue / work item is attached
• Tests are written (if applicable)
• Documentation is updated (if applicable)
• Changes are tested and related VM images are successfully generated

[Copilot]

Pull request overview

This pull request aims to add docker-cli installation to the ubuntu-slim image, fix apt source configurations to use the standard Ubuntu archive instead of Azure's mirror, and preserve apt package lists during cleanup. The changes address two reported issues: #13464 and #13426.

Key Changes:

• Adds docker-cli installation and corresponding test
• Modifies apt source configuration to use archive.ubuntu.com instead of azure.archive.ubuntu.com
• Removes cleanup of /var/lib/apt/lists/* to keep apt package lists available
• Adds set -eo pipefail temporarily during Docker build for better error handling

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
images/ubuntu-slim/test.sh	Adds pipefail option and test for docker-cli installation
images/ubuntu-slim/scripts/helpers/cleanup.sh	Removes deletion of apt lists to keep them available
images/ubuntu-slim/scripts/build/configure-apt.sh	Removes redundant unattended-upgrades purge and jq installation code
images/ubuntu-slim/scripts/build/configure-apt-sources.sh	Changes apt source URL from azure.archive to archive.ubuntu.com
images/ubuntu-slim/Dockerfile	Adds docker-cli installation script invocation and temporary pipefail configuration

[Copilot]

The script 'install-docker-cli.sh' is referenced here but does not appear to exist in the repository. This will cause the Docker build to fail when it reaches this line. You need to either create the missing installation script or remove this line if docker-cli installation is not yet ready.

Suggested change

/tmp/scripts/build/install-docker-cli.sh && \

[Copilot]

The test for docker-cli is added here, but the corresponding installation script (install-docker-cli.sh) referenced in the Dockerfile does not exist in the repository. This test will fail until the installation script is added.

Suggested change

	run_test "docker-cli is installed" docker --version
	# NOTE: docker-cli is not currently installed by this image; re-enable this test
	# once the corresponding installation script is added to the build.
	# run_test "docker-cli is installed" docker --version

[Copilot]

The 'set -eo pipefail' command is temporarily added to /etc/bash.bashrc during the build and then removed after all installation scripts complete. However, the test.sh file uses 'set -o pipefail' (without the 'e' flag). For consistency, consider using the same flags in both places, or document why different flags are used. The 'e' flag causes the shell to exit on any error, which may be desired during the build but not necessarily in the test script.

Suggested change

	set -o pipefail
	set -eo pipefail

[Copilot]

There is trailing whitespace on this otherwise empty line. Consider removing it to maintain consistent formatting.

Suggested change

[kixorz]

This is useful, can you maybe finish it and merge it?