Retrieves a continuation (resume) URL for a previously-started, in-progress onboarding session.

This allows an end-user to return to their onboarding process after leaving the session without completing it.

Important:

The onboardingId must be taken from the response returned by the onboarding creation endpoint (POST /onboardings/company, /association, /sole_trader, /individual).

This ID is mandatory and must be included in the request path