add farnoosh and anoop as CODEOWNERS for metrics

Why is this change being made?

The metrics page is an import SSOT for defintions of metrics used at GitLab. We want to ensure that @fseifoddini and @adawar are CODEOWNERS and notified of changes to that file.

Does this MR meet the acceptance criteria?

Assign to DRI

• Did you assign this change to the correct DRI of the page or information you are changing?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what