Template-less exporters don't render variables

[mangelajo]

For an exporter instance of this form:

apiVersion: meta.jumpstarter.dev/v1alpha1
kind: ExporterInstance
metadata:
name: ti-am69-eballetbo-01
spec:

this is a desk-user device, we do not track location, and we don't manage the host

we let authentication with the OIDC provider

username: rh:eballetbo
labels: # adds or overrides the template labels which will be applied to the exporter
device: "$( params.name )"
board: ti-am69
ram: "32"
cpu: "8"
emmc: "true"
sd: "true"
location: "eballetbo-desk"
jumpstarterInstanceRef:
name: "jumpstarter-auto-devcluster"

Creating exporter ti-am69-eballetbo-01 in namespace jumpstarter-lab
Error: error syncing exporters for jumpstarter-auto-devcluster: [jumpstarter-auto-devcluster] failed to create exporter ti-am69-eballetbo-01: Exporter.jumpstarter.dev "ti-am69-eballetbo-01" is invalid: metadata.labels: Invalid value: "$( params.name )": a valid label must be an empty string or consist of alphanumeric characters, '-', '' or '.', and must start and end with an alphanumeric character (e.g. 'MyValue', or 'my_value', or '12345', regex used for validation is '(([A-Za-z0-9][-A-Za-z0-9.]*)?[A-Za-z0-9])?')