Remove the group selector when submitting the survey with "Submit this draft to..."

When you submit a survey, you are provided a screen saying "Confirm Submission" and "Submit this draft to..." with the name of the group. Users may change the submission group route at this point, which in the new structure should not be possible. We need to remove this option so users cannot change the route on submission. However, we should retain the confirmation message saying "Submit this draft to ?". In the future, especially with rights and roles, we'll probably further improve this screen, but for now remove the option to change group and make it an informative message only. (#355)