Ensure drag-drop GCode is disallowed on part tabs
Ensure drag-drop GCode is disallowed on part tabs

- Issue MatterHackers/MCCentral#3318
Drag-drop GCode to part tab should not be allowed

larsbrubaker/MatterControl,jlewin/MatterControl,larsbrubaker/MatterControl,larsbrubaker/MatterControl,mmoening/MatterControl,jlewin/MatterControl,mmoening/MatterControl,mmoening/MatterControl,unlimitedbacon/MatterControl,larsbrubaker/MatterControl,unlimitedbacon/MatterControl,jlewin/MatterControl,unlimitedbacon/MatterControl,unlimitedbacon/MatterControl,jlewin/MatterControl