Clear the pause markers and restore the renewal schedule that was stashed in previous_renew_time when the audience was paused.

Refuses with 409 Conflict when the audience is paused for a reason other than manual:

• pause_reason = "org_inactive": the parent organization must be reactivated before any of its audiences can be resumed. Response body includes "code": "org_inactive".
• pause_reason = "project_inactive": the parent project must be reactivated first. Response body includes "code": "project_inactive".

Returns 409 Conflict with no code field when the audience is not paused at all.