fix: remove aptmarkwalinuxAgent hold/unhold from cse main

[SriHarsha001]

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

[Copilot]

Pull request overview

This PR updates the Linux CSE entrypoint (cse_main.sh) to stop holding/unholding the walinuxagent package via aptmarkWALinuxAgent from the main flow, and regenerates the corresponding CustomData snapshot test artifacts in pkg/agent/testdata/ to reflect the new rendered script output.

Changes:

• Removed aptmarkWALinuxAgent hold from basePrep in cse_main.sh.
• Removed aptmarkWALinuxAgent unhold from nodePrep in cse_main.sh (both reboot-required and non-reboot paths).
• Regenerated multiple pkg/agent/testdata/**/CustomData* snapshot files to match updated CSE output.

Reviewed changes

Copilot reviewed 63 out of 66 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
parts/linux/cloud-init/artifacts/cse_main.sh	Removes aptmark walinuxagent hold/unhold calls from the main provisioning flow.
pkg/agent/testdata/MarinerV2+Kata/CustomData	Regenerated rendered CustomData snapshot (gzip/base64 blob changed).
pkg/agent/testdata/MarinerV2+CustomCloud/CustomData	Regenerated rendered CustomData snapshot (gzip/base64 blob changed).
pkg/agent/testdata/Flatcar/CustomData.inner	Regenerated rendered ignition/customdata snapshot payload.
pkg/agent/testdata/Flatcar+CustomCloud/CustomData.inner	Regenerated rendered ignition/customdata snapshot payload.
pkg/agent/testdata/CustomizedImageLinuxGuard/CustomData	Regenerated rendered CustomData snapshot (gzip/base64 blob changed).
pkg/agent/testdata/CustomizedImageKata/CustomData	Regenerated rendered CustomData snapshot (gzip/base64 blob changed).
pkg/agent/testdata/CustomizedImage/CustomData	Regenerated rendered CustomData snapshot (gzip/base64 blob changed).
pkg/agent/testdata/AzureLinuxV3+Kata/CustomData	Regenerated rendered CustomData snapshot (gzip/base64 blob changed).
pkg/agent/testdata/AzureLinuxV2+Kata/CustomData	Regenerated rendered CustomData snapshot (gzip/base64 blob changed).
pkg/agent/testdata/AKSUbuntu2404+Teleport/CustomData	Regenerated rendered CustomData snapshot (gzip/base64 blob changed).
pkg/agent/testdata/AKSUbuntu2204+China/CustomData	Regenerated rendered CustomData snapshot (gzip/base64 blob changed).

Comments suppressed due to low confidence (2)

parts/linux/cloud-init/artifacts/cse_main.sh:478

• aptmarkWALinuxAgent unhold has been removed from nodePrep, but installDeps (ubuntu/cse_install_ubuntu.sh) still runs aptmarkWALinuxAgent hold before apt operations. With this change, walinuxagent can remain held indefinitely after provisioning, preventing future package updates. Either remove the hold in installDeps as well, or reintroduce an explicit unhold at the appropriate completion point (including the reboot-required path).

    if $REBOOTREQUIRED; then
        echo 'reboot required, rebooting node in 1 minute'
        /bin/bash -c "shutdown -r 1 &"
    else
        if [ "$OS" = "$UBUNTU_OS_NAME" ]; then
            # logs_to_events should not be run on & commands
            if [ "${ENABLE_UNATTENDED_UPGRADES}" = "true" ]; then

parts/linux/cloud-init/artifacts/cse_main.sh:478

• The comment # logs_to_events should not be run on & commands is now misleading in this Ubuntu branch since the only & invocation that used to follow (aptmark unhold) was removed. Consider deleting or relocating the comment to where it still applies to avoid confusion.

        if [ "$OS" = "$UBUNTU_OS_NAME" ]; then
            # logs_to_events should not be run on & commands
            if [ "${ENABLE_UNATTENDED_UPGRADES}" = "true" ]; then