• Harden function to get Discord server mapping.
• Fix group sync position tracking not being displayed correctly.

• When sending a notification to Discord, include the author's avatar if they have one.
• Handle cases where optout value may be nulled out.
• Simplify the process of opting in to mirrored Discord alerts to prevent confusion.
• Add an option to announce new associations to a specific Discord channel.
• If usernames are being synced, ensure any username changes to Discord are synced too.
• Add an option to kick users from your Discord server if they disconnect their forum account.
• If a user is banned on your forum, this will now be mapped to Discord properly rather than disconnecting them.
• Fix blocking user creation when add-on is disabled.
• Minor rework of the option to prevent registering and/or logging in with Discord.
• Add missing user change log phrase.