UI: suppress Copy/Paste/Edit Driver options on whole array property fields.

When a button represents the whole array (e.g. color picker buttons),
these context menu options were available, but didn't really work
correctly. Since it's not clear how they could reasonably work without
a valid index, it's better to hide them.

source/blender/editors/interface/interface_ops.c

@@ -172,7 +172,8 @@ static bool copy_as_driver_button_poll(bContext *C)
   UI_context_active_but_prop_get(C, &ptr, &prop, &index);
 
   if (ptr.id.data && ptr.data && prop &&
-      ELEM(RNA_property_type(prop), PROP_BOOLEAN, PROP_INT, PROP_FLOAT, PROP_ENUM)) {
+      ELEM(RNA_property_type(prop), PROP_BOOLEAN, PROP_INT, PROP_FLOAT, PROP_ENUM) &&
+      (index >= 0 || !RNA_property_array_check(prop))) {
     path = RNA_path_from_ID_to_property(&ptr, prop);
 
     if (path) {