chore: use renovate for waagent version, write to release notes, add log-checking e2e

[mxj220]

What this PR does / why we need it:

• use renovate to track waagent version
• write to release notes
• add log-checking e2e

Which issue(s) this PR fixes:

Fixes #

[Copilot]

Pull request overview

This PR moves WALinuxAgent (waagent) version tracking into parts/common/components.json (so Renovate can update it), logs the installed waagent version into the VHD release notes, and adds an e2e validator that inspects /var/log/waagent.log to confirm expected behavior/version.

Changes:

• Add a walinuxagent package entry to parts/common/components.json and configure Renovate to update github-releases= tags.
• Update the post-deprovision waagent install flow to read the target version from components.json, pass it into the installer, and append it to vhd-install.complete.
• Add a new e2e validator (ValidateWaagentLog) and wire it into the common Linux validation flow.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
vhdbuilder/packer/test/linux-vhd-content-test.sh	Updates test commentary around waagent installation expectations.
vhdbuilder/packer/post-deprovision-walinuxagent.sh	Reads waagent version from /opt/azure/components.json, passes it to the installer, and logs to VHD release notes.
vhdbuilder/packer/install_walinuxagent.py	Changes installer to accept an explicit version argument (from components.json) instead of deriving version from GAFamily.
parts/common/components.json	Adds walinuxagent entry with Renovate tag targeting GitHub releases.
e2e/validators.go	Adds ValidateWaagentLog validator that checks waagent logs for expected behavior/version.
e2e/validation.go	Runs ValidateWaagentLog as part of ValidateCommonLinux.
.github/renovate.json	Adds a custom Renovate regex manager for github-releases= renovateTag entries in components.json.