Ensure that 'Phone number' is set for Azure Security Center Contact

'Phone number' is NOT set for Azure Security Center Contact, this may hamper incident response.

According to Microsoft, Owner access level is required to make any changes to the Defender for Cloud contact information. To do so, follow the steps outlined in the Azure Documentation.

In Terraform -

1. In the azurerm_security_center_contact resource, add a phone number.

References:
https://learn.microsoft.com/en-us/azure/defender-for-cloud/configure-email-notifications
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/security_center_contact#phone