private dns zone will omit tags when the key containing ":"

we are using api-version "2018-09-01". when creating a private dns zone, the tags will be omited when the key contains `:`. However, in other azure service, there is no such behaviour

https://github.com/terraform-providers/terraform-provider-azurerm/issues/6129

Start by reviewing the Azure Private DNS Zone specification for API version 2018-09-01 and the linked Terraform issue. Confirm how tag keys containing ":" are represented during creation, then update the specification if needed so those tags are preserved consistently with other Azure services.

Written by the indexing model from the issue text.