Start the monarch-zenoz.js card fields on a merchant's checkout page using a publishable key.

The script calls this for you from the browser. The page's Origin must be on the key's allowed origins.

Errors to handle:

• 403 ORIGIN_NOT_ALLOWED: the page's origin is not on the key's list.
• 401 ENVIRONMENT_MISMATCH: the key belongs to a different environment (for example a pk_test_ key on production).
• 401 INVALID_PUBLISHABLE_KEY: the key is unknown, revoked, or past its rotation grace period.