RVT sample texture param ignores groups.

RVT texture sample params ignore groups and ignore existing groups.

• Create a material.
• Add a RVT sample node.
• Convert it to a param.
• Set a group for the param (notice it also ignore all existing groups as there is no drop down menu).
• Save and create a material instance.
• Open the material instance and you won't see the RVT parm in the assigned group.