The Bug:

You can insert special characters into the "Invite player" field despite usernames being unable to contain them.

Steps to Reproduce:

1. Navigate to the minecraft realms menu.
2. Click on your realm and hit the "configure realm" button.
3. Hit the "players" button and then the "invite player" button.
4. Type some special characters into the "invite player" field.
5. Take note as to whether or not you can insert special characters into the "Invite player" field despite usernames being unable to contain them.

Observed Behavior:

You can insert special characters into the "Invite player" field.

Expected Behavior:

You would not be able to insert special characters into the "Invite player" field.