Introduce getAvatarForUser in avatar-utils. getAvatarForUser is a function that checks if a user has an avatar, and either returns that or randomly generates an emoji avatar for the user and returns that. We generate an emoji avatar based on the user's username. If the user does not have a username set, we just default to an avatar with this emoji π€ for the user.
This diff won't be landed until there is a feature flag for the avatars work
Linear Task: https://linear.app/comm/issue/ENG-3257/create-function-to-automatically-select-an-emoji-avatar-for-users-with