feat: add emoji to button
Emojis should follow the design pattern laid out, which is that they are to the left of the text and have a right margin of 8px.
They are also 16px in a normal button and 12px in a small button.
They utilize the selected
attribute to designate
the user has already chosen that emoji.
Closes gitlab#30282 (closed)
Closes gitlab#30296 (closed)