Address review feedback on #14199: deleting and recreating the legend left
views bound to the old legend pointing at a deleted object. Add
RimColorLegendCollection::updateColorLegend and a matching UpdateColorLegend
scriptable method that mutate the existing custom legend (name and items) so
referring views keep their binding and are notified once. A new legend is only
created when none is registered for the result or the registered legend is a
standard legend.
set_discrete_property_category_names now performs a single atomic call instead
of delete + create + per-item appends. The empty-dict removal path still uses
DeleteColorLegend.
Kristian Bendiksen
Magne Sjaastad
Gaute Lindkvist