Update the IsPlatformAlertRule logic to check the prometheusRule namespace for a the cluster-monitoring label.
This labels defines if the alert rules will be evaluated by the platform or user stacks.

In addition, For Alert rules:
openshift_io_rule_managed_by
user rule:
operator - ownerreffernce
gitops - includes the git ops label

platform rule
operator - default
gitops - includes the git ops label

openshift_io_relabel_config_managed_by
platform rule:
gitops