Link to user page on helper dashboard in user-facing message

[MMK21Hub]

There should be a link to the question author's user page on helper dashboard in user-facing the message! Or at least a link to https://flavortown.hackclub.com/helper/users?query=[SLACKID]

At the moment, the workflow to get troubleshooting info for a user is:

1. Right-click Slack account
2. Copy link
3. Get the user ID from that link
4. Go to Flavortown, click Helper, click Users
5. Paste the user ID, press enter
6. Click View
7. Optionally click onto one of their projects

It's be much better if this was only a few clicks!

[MMK21Hub]

Note that this should be done within the Flavortown transcript file, maybe once we've got Jinja templates (#127) so we can do {author.slack_id}