Ensure public access is disabled for Azure MSSQL Server

Allowing unrestricted, public access to cloud services could open an application up to external attack. Disallowing this access is typically considered best practice.

In Azure Console -

1. Open the Azure Portal and go to SQL servers.
2. Choose the SQL server you wish to edit.
3. Under Networking, Set Public network access to Disable
4. Select Save

In Terraform -

1. In the azurerm_mssql_server resource, set public_network_access_enabled to false.

References:
https://learn.microsoft.com/en-us/azure/azure-sql/database/connectivity-settings?view=azuresql&tabs=azure-portal
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/mssql_server#public_network_access_enabled