Creation of nested folders is not possible in
`project-type: folder` in test mode because the
folder name conflicts with the generated XML
filename and an `OSError` is thrown as a result.
This can be resolved by passing the `--config-xml`
flag when running the jobs in test mode. This
commit displays a deprecation message asking the
user to use the `--config-xml` flag.
Change-Id: I6f883040ed3d9b3536ccc2fb305cdddcfde5d765
Story: #2001937
Task: #15050