Blender Git Loki

UI: Support setting operator properties for `UILayout.operator_menu_enum()`

`UILayout.operator_menu_enum()` now returns the operator properties, just like
`UILayout.operator()`. This makes it possible to set options for the operator
displayed in the menu. In C it can be done through the new
`uiItemMenuEnumFullO()` or `uiItemMenuEnumFullO_ptr()`.

It's reasonable to have this, probably just a small thing never bothered to
add. D10912 could use it, the following comment can be addressed now too:
https://developer.blender.org/diffusion/B/browse/master/source/blender/editors/space_nla/nla_buttons.c$583-586