Using Databricks Runtime 12.0, when attempting to mount an Azure blob storage container, I'm getting the following exception:

`IllegalArgumentException: Unsupported Azure Scheme: abfss`

dbutils.fs.mount(
    source="abfss://container@my-storage-account.dfs.core.windows.net/",
    mount_point="/mnt/my-mount-point"
  )

I can succesfully list files using `dbutils.fs.ls`, it's just the mounting that does not work.