This PR adds the ability to update the last_used_at and/or locked_at fields for template workspaces when updating the template scheduling form. This is to prevent updates to the inactivity_ttl or locked_ttl fields on a template having a potentially unintended effect for existing workspaces.

e.g. You update the locked_ttl field to retain locked workspaces for 1 day from 10 days, inadvertently deleting workspaces that have already been locked for more than 1 day.