Notification settings in Alert rule group not sync'ed

[chauvm]

Describe the bug
When creating a GrafanaAlertRuleGroup with association with a contact point, the association is not created.

Version
v5.12.0

To Reproduce
Steps to reproduce the behavior:

1. Go to Grafana and export a rule group that has a contact point as the notification policy
2. Use the rule to add to a GrafanaAlertRuleGroup manifest's spec.rules

apiVersion: grafana.integreatly.org/v1beta1
kind: GrafanaAlertRuleGroup
metadata: ...
spec:
  rules:
    - annotations: ...
      data:
        - datasourceUid:...
      notification_settings:
        receiver: my-contact-point
      title: ...
      uid: ...

3. From ArgoCD, see that the created alert rule group doesn't have the notification_settings.receiver, and from Grafana confirm that there's no such association.

Expected behavior
The alert rule should have linked correctly to the contact point.

Suspect component/Location where the bug might be occurring
Unknown. Not sure if this is related, but my contact point also has this bug #1644.

Screenshots
If applicable, add screenshots to help explain your problem.

Runtime (please complete the following information):

• OS: [e.g. Linux,Fedora,Mac]
• Grafana Operator Version [e.g. v5.0.0]: v5.12.0
• Environment: [e.g Openshift,Kubernetes,minikube etc. please specify versions]
• Deployment type: [e.g Openshift OLM/Helm/kustomize]
• Other: [Other variables/things that might be relevant to this bug, versions of other services e.g. operator-sdk]

Additional context
Add any other context about the problem here.

[theSuess]

To keep in line with kubernetes convention, the operator uses notificationSettings instead of notification_settings