Checkmk Werk 11876: Dashboard: Prevent exception when trying to copy view to dashboard

ID: 11876 Title: Dashboard: Prevent exception when trying to copy view to dashboard Component: Multisite Level: 1 Class: Bug fix Version: 2.1.0i1 When trying to copy a view to a dashboard without selecting a view name, this lead to an exception in the resulting dialog. The form is now preventing an empty selection.