[Databricks module] Replace deprecated resource for new resource

[jdocampo]

As seen in the tests:

│ Warning: Argument is deprecated
│ 
│   with azurerm_databricks_workspace_customer_managed_key.adl_adb_ws_cmk,
│   on databricks.tf line 41, in resource "azurerm_databricks_workspace_customer_managed_key" "adl_adb_ws_cmk":
│   41:   workspace_id     = module.databricks.id
│ 
│ this resource has been deprecated in favour of the
│ `azurerm_databricks_workspace_root_dbfs_customer_managed_key` resource and
│ will be removed from the v4.0 azurerm provider.

The azurerm_databricks_workspace_customer_managed_key resource in the tests should be replaced by azurerm_databricks_workspace_root_dbfs_customer_managed_key