Is there any policy on the use of emojis or emoticons?
In https://askubuntu.com/posts/1105109/revisions it was part of the code until the querist removed it
I think the existing rules apply: if something isn't adding relevant information to a post, it is noise and it is better to remove it. Unless a question is actually about emojis, they don't add anything useful to a post, so I don't see why they should be treated any differently to any other type of noise.
More importantly, emojis often don't render correctly across different browsers and platforms, making it an even worse idea to include them in posts. So no, please don't include emojis in AU questions or answers unless they really are necessary for some reason.