Older ARO SKU references in Machine Sets after ARO cluster upgrade

Key takeaways

• There is no need to modify the aro_412 SKU when upgrading to newer OCP releases.
• The MachineConfigOperator (MCO) applies the correct OS configuration during ignition.
• Red Hat recently introduced the ability to change SKUs in Google Cloud and AWS, but there is no Azure support yet.
• Modifying the boot image (SKU) manually in AR...