Summary:
This allows us to mark targets as manual build and not bazel ignore them.

We need to add a linter to make sure we follow this rule.

Test Plan: bazel test //...

Reviewers: oazizi, michelle, #engineering

Reviewed By: oazizi, #engineering

Differential Revision: https://phab.corp.pixielabs.ai/D1122

GitOrigin-RevId: f47fd0d4725d3d5be9a12a07dbf6a2665c563196