Update learn more docs

What does this MR do?

• Updates documentation to set up generic alert endpoint
• Removes check for empty link since it's being added here

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• [-] Merge request performance guidelines
• [-] Style guides
• [-] Database guides

https://gitlab.com/gitlab-org/gitlab-ce/issues/65285