Remove `undefined` class from `.emoji-menu-list`

What does this MR do?

• Remove undefined class from .emoji-menu-list

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

• undefined was showing up in the class attribute of the .emoji-menu-list

Does this MR meet the acceptance criteria?

• Tests
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #30496 (closed)

added ~128341 label

Thanks @MadLittleMods! ✨

changed milestone to %9.1

merged

mentioned in commit 2d246df5

mentioned in commit a1382018

mentioned in commit 174dca9d

mentioned in commit 75ded1c7