DevTools: Workbench - Unable to create a new Folder in content design view

[natechadwick]

Describe the bug

This looks like a regression introduced by one of the commits for #1108 . You are unable to create grouping folders in the Content Design view of the workbench.

To Reproduce

Steps to reproduce the behavior:

1. Install the dev tools'
2. Install latest 8.1.4-snapshot
3. Start CMS
4. Run Workbench.cmd
5. Connect the workbench to the CMS
6. From the Content Design View, Select the new-Folder option. The above error will be displayed.

Expected behavior

A new folder should be created in the workbench view without error.

Versions Affected

• 8.1.4-SNAPSHOT

Additional context

Server log has the following errors:

09:24:10,885 ERROR [Web Services] SOAP Invalid Contract for service createHierarchyNodes
java.lang.IllegalArgumentException: name must be unique in parent node
        at com.percussion.services.ui.impl.PSUiService.createHierarchyNode(PSUiService.java:72) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_381]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_381]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_381]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_381]