Get declined requirements

Deprecated alias of /v1/phone-numbers/{id}/remediate; same contract. New integrations should use that path.

For a number in regulatory_declined, returns ONLY the requirements the reviewer flagged declined, as a form spec (same shape as the KYC form GET). The customer fixes just those — Telnyx supports correcting a declined requirement group and re-submitting it (no new number/group). Falls back to the full spec if the provider exposes no per-requirement flags.