This user story will cover changes for both 4.19 and after back porting it to 4.18.
I need to validate that OpenShift clusters using cgroupv1 cannot upgrade. The upgrade process should detect cgroupv1 and prevent the upgrade by setting the Upgradeable=False condition on the machine-config operator.

Test Scenarios:
Scenario 1:
Ensure Upgrade is Blocked When Using CgroupV1
Given: An OpenShift 4.17 cluster where cgroupMode is set to v1 when the user attempts to upgrade to OCP 4.18 then the upgrade process should not start.
The machine-config operator (MCO) should report Upgradeable=False.
The error message should clearly indicate that cgroupMode must be switched to v2 before proceeding.

Scenario 2:
Verify Upgrade is Allowed After Switching to CgroupV2
Given: An OpenShift 4.18 cluster initially set to cgroupMode=v1
When the user updates the cgroupMode to v2 using oc edit nodes.config.openshift.io cluster.The Machine Config Operator (MCO) applies the changes across all nodes.
The user attempts to upgrade to 4.19.
Then the machine-config operator should report Upgradeable=True.
The cluster should successfully proceed with the upgrade to 4.19.