Fix: GPv3: Assert opening overlay panel in sculpt mode

Assert is due to wrong bounds passed to `std::clamp`. There seems no
error in UI code, instead this occurs due to `layout.label()`. It
returns an error due to missing case of `SCULPT_GREASE_PENCIL`. Due to
the error, panel is not generated with properties and the `rect-> min/max`
remained short enough to trigger assert

Pull Request: https://projects.blender.org/blender/blender/pulls/123478

scripts/startup/bl_ui/space_view3d.py

@@ -8200,6 +8200,7 @@ class VIEW3D_PT_overlay_grease_pencil_options(Panel):
             'EDIT_GREASE_PENCIL': iface_("Edit Grease Pencil"),
             'WEIGHT_GREASE_PENCIL': iface_("Weight Grease Pencil"),
             'OBJECT': iface_("Grease Pencil"),
+            'SCULPT_GREASE_PENCIL': iface_("Sculpt Grease Pencil"),
         }[context.mode], translate=False)
 
         layout.prop(overlay, "use_gpencil_onion_skin", text="Onion Skin")