When users encounter a policy exception for a non-view capability with a custom policy, inline the policy rules

Summary:
Fixes T13411. This looks like the last case where you hit a policy explanation and have permission to see the policy, but we don't currently show you the policy rules.

This implementation is slightly clumsy, but likely harmless.

Test Plan:

Maniphest Tasks: T13411

Differential Revision: https://secure.phabricator.com/D20807