Update campaign settings (v2)

Save a Discovery campaign's settings in place, all or nothing: its name, assistants, customers (who and how many) and a store campaign's stores. Results continue on the same campaign and take in the change over its next 30 days; changes reach the next run, and a run under way finishes on what it reserved. Nothing is charged at Save: delivered conversations accrue against the plan, and a Save adding work Billing would not admit is refused. Pass expectedSettingsRevision from discovery_campaign_settings_get; a Save whose settings moved since is refused (STALE_WRITE). Pass reviewedEstimate from discovery_campaign_settings_quotes_get_v2 to also refuse one whose estimate moved, or null to save at the current estimate. The website and the audiences it launched with never change. A person confirms it.