Blender Git Loki

Geometry Nodes: Expose the active modifier to the UI

This exposes the operator to set the active modifier as the type icon
in the header of the modifier panels. Tweaks to the widget drawing
code were necessary to use the red alert for non-emboss operator
buttons. Then, the panel for the active modifier gets a border around it
(which currently uses the property search theme color), requiring
an "active property" field in the PanelType struct.