Curves: Don't allow resolutions less than 1

While this worked, the result for curves with a resolution of zero was
just a single evaluated point, which isn't useful or intuitive. Using
the attribute validation from 8934f00ac5, make sure users
can't set values 0 or less.

source/blender/blenkernel/BKE_curves.hh

@@ -218,7 +218,7 @@ class CurvesGeometry : public ::CurvesGeometry {
 
   /**
    * How many evaluated points to create for each segment when evaluating Bezier,
-   * Catmull Rom, and NURBS curves. On the curve domain. Values must be zero or greater.
+   * Catmull Rom, and NURBS curves. On the curve domain. Values must be one or greater.
    */
   VArray<int> resolution() const;
   /** Mutable access to curve resolution. Call #tag_topology_changed after changes. */

source/blender/blenkernel/intern/geometry_component_curves.cc

@@ -548,7 +548,7 @@ static ComponentAttributeProviders create_attribute_providers_for_curve()
 
   static const fn::CustomMF_SI_SO<int, int> resolution_clamp{
       "Resolution Validate",
-      [](int value) { return std::max<int>(value, 0); },
+      [](int value) { return std::max<int>(value, 1); },
       fn::CustomMF_presets::AllSpanOrSingle()};
   static BuiltinCustomDataLayerProvider resolution("resolution",
                                                    ATTR_DOMAIN_CURVE,