Azure ML template uses deprecated Terraform

[SvenAelterman]

Describe the bug

While building the Azure ML template, I received this Terraform warning:

│ Warning: Deprecated attribute
│ 
│   on main.tf line 23, in resource "azurerm_machine_learning_workspace" "aml_workspace":
│   23:       public_access_behind_virtual_network_enabled
│ 
│ The attribute "public_access_behind_virtual_network_enabled" is deprecated. Refer to the provider documentation for details.

Azure TRE release version (e.g. v0.14.0 or main): v0.15.2

Deployed Azure TRE components - click the (i) in the UI:
UI Version:
0.5.15
API Version:
0.15.17

[tim-p-allen]

#3919