Fix T81953: Python error in UV Editor Overlay popup

Leftover from rBe05ce1ea2029, 'use_image_editor_legacy_drawing' was
removed.

Maniphest Tasks: T81953

Differential Revision: https://developer.blender.org/D9310

release/scripts/startup/bl_ui/space_image.py

@@ -1521,8 +1521,6 @@ class IMAGE_PT_overlay_uv_edit_geometry(Panel):
         col = layout.column()
         col.prop(uvedit, "uv_opacity")
         col.prop(uvedit, "edge_display_type", text="")
-        if context.preferences.experimental.use_image_editor_legacy_drawing:
-          col.prop(uvedit, "show_smooth_edges", text="Smooth")
         col.prop(uvedit, "show_modified_edges", text="Modified Edges")
 
         # Faces