Fix #116188: hair puff works incorrect with symmetry

Originally caused by 1b19f62917 .

Solution is the same as ff7b8f3412
Only this time it does the same thing `Sphere` falloff (whereas
ff7b8f3412 fixed it for `Projected` falloff)

Pull Request: https://projects.blender.org/blender/blender/pulls/117987

source/blender/editors/sculpt_paint/curves_sculpt_puff.cc

@@ -260,7 +260,7 @@ struct PuffOperationExecutor {
             brush_, dist_to_brush_cu, brush_radius_cu);
         math::max_inplace(max_weight, radius_falloff);
       }
-      r_curve_weights[curve_i] = max_weight;
+      math::max_inplace(r_curve_weights[curve_i], max_weight);
     });
   }