Ensure public network access is disabled for Azure Batch Account

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 Batch Account.
2. Select the Batch Service you want.
3. Select the Networking Tab and under 'Public network access', choose 'Disabled'.

In Terraform -

1. In the azurerm_batch_account resource, set 'public_network_access_enabled' to 'false'. By default 'public_network_access_enabled' is set to 'true'.

References:
https://learn.microsoft.com/en-us/azure/batch/public-network-access
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/batch_account#public_network_access_enabled