Fix T73186: Grease Pencil convert to Curve hidden until exiting edit mode

The converted object wasn't tagged for updating its geometry in the
dependency graph.

source/blender/editors/gpencil/gpencil_convert.c

@@ -1390,6 +1390,8 @@ static void gp_layer_to_curve(bContext *C,
   }
 
   ED_object_base_select(base_new, BA_SELECT);
+
+  DEG_id_tag_update(&ob->id, ID_RECALC_GEOMETRY);
 }
 
 /* --- */