Correctly associate ConvDev Index nav link with its controller

What does this MR do?

Ensures that the Monitoring sub menu is not associated with the ConvDev Index nav item.

Recording

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/37583