Re-work help text on Edit profile page
Problem
In making a few small UI changes as part of !142472 (merged), spotted that there are three help messages that utilize "Learn more" links, which Pajamas says we shouldn't do:
If you can't determine a useful question, use Learn more. However, be aware that Learn more is not descriptive or meaningful, and should be used sparingly.
Can we re-work the help text on the commit email, Discord and Private profile fields to better align it with Pajamas by removing the "Learn more" links?
Implementation Guide
Update the following three help messages as follows:
Commit email: This email address is used for web-based operations, such as edits and merges. [What is a private commit email?](https://docs.gitlab.com/ee/user/profile/index.html#use-an-automatically-generated-private-commit-email)
Discord field: Your Discord user ID.
Private profile: Don't display activity-related personal information on your profile. [What information is hidden?](https://docs.gitlab.com/ee/user/profile/index.html#make-your-user-profile-page-private)
Note: at least one of the existing "Learn more" links is used in a test so, tests will likely also need updating when the text is changed.