fix: unfreeze 2204 kernel to pick up new one which has CVE fixes in 1109

[awesomenix]

pickup new kernel to address CVE fixes

[Copilot]

Pull request overview

This PR removes the Ubuntu 22.04-specific kernel pin in the VHD build so Ubuntu 22.04 images can pick up newer Azure LTS kernel builds that include recent CVE fixes.

Changes:

• Removed the explicit pin to linux-image-5.15.0-1102-azure for Ubuntu 22.04.
• Allowed Ubuntu 22.04 to follow the standard linux-image-azure-lts-22.04 package path (same pattern as other supported Ubuntu releases).

Comments suppressed due to low confidence (1)

vhdbuilder/packer/pre-install-dependencies.sh:158

• Removing the Ubuntu 22.04 kernel pin here will change the resulting uname -r on built images, but the VHD content test still expects an exact 5.15.0-1102-azure kernel for 22.04 non-CVM builds (see vhdbuilder/packer/test/linux-vhd-content-test.sh around testLtsKernel). Update that test expectation (or relax it to a major/minor match) so CI doesn’t fail once 22.04 starts picking up newer kernels (e.g., 1109).

  else
    # Use LTS kernel for other versions
    KERNEL_IMAGE="linux-image-azure-lts-${UBUNTU_RELEASE}"
    KERNEL_PACKAGES=(
      "linux-image-azure-lts-${UBUNTU_RELEASE}"
      "linux-tools-azure-lts-${UBUNTU_RELEASE}"
      "linux-cloud-tools-azure-lts-${UBUNTU_RELEASE}"
      "linux-headers-azure-lts-${UBUNTU_RELEASE}"
      "linux-modules-extra-azure-lts-${UBUNTU_RELEASE}"
    )
    echo "Installing LTS kernel for Ubuntu ${UBUNTU_RELEASE}"
  fi