Fix T53800: Bad data editing during DEG evaluation?

Remain convinced that it should not be possible for undo code to run in
parallel with DEG eval... But for now, this whould prevent static
override code to dive into this collection.

source/blender/makesrna/intern/rna_object.c

@@ -2835,6 +2835,7 @@ static void rna_def_object(BlenderRNA *brna)
 	                                  NULL,
 	                                  NULL);
 	RNA_def_property_struct_type(prop, "LayerCollectionSettings");
+	RNA_def_property_flag(prop, PROP_NO_COMPARISON);  /* XXX see T53800. */
 	RNA_def_property_ui_text(prop, "Collection Settings",
 	                         "Engine specific render settings to be overridden by collections");