List SMS phone numbers

Retrieve your SMS sending identities: phone numbers and alphanumeric Sender IDs. Only entries with status: "active" can send; a ten_dlc number has no phone_number until carriers approve the registration, a long_code is a local number issued outside the US (Canada today: country: "CA", reach: ["CA"], no carrier registration, use_case: null), and a simulator number only delivers to verified test destinations. use_case is what carriers approved the number to send. A sender_id entry is one country of a Sender ID: the identity is ONE string per brand enabled per country, the list returns one entry per (Sender ID, country), and every entry carries sender_id_group with the whole country set so you can group them. Requesting or releasing an identity is only available in the dashboard. Requires the sms:read capability.