Resolve CE/EE in repo check mailer notify html

What does this MR do?

This resolves the CE/EE difference in app/views/repository_check_mailer/notify.html.haml. It follows the same solution that was in app/views/repository_check_mailer/notify.text.haml.

Screenshots

They're the same 😄

Before	After

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
• Separation of EE specific content

Links

Closes #10446 (closed)