getMissingParameters on the frontend does a best effort to detect if a workspace update will fail due to it's previous parameter values.

1 of the criteria is to check if the value is in the set of options for the parameter. This is an incomplete validation, as things such as regex, type, etc can also be changed template version to template version.

The frontend should ask the backend to do a validation check and actually check all criteria. (Check diagostics on a param?)