Get Participant Form Data

Returns decrypted, labeled form submission data for all form requests linked to the given participant.

Covers two linkage scenarios:

1. form_request.linked_participant_id = participant_id (explicit pre-link)
2. form_request.processing_outcomes['Participant Lead Created'] = str(participant_id) (participant created from the form on completion)

Results are scoped to the given plan_manager_id for security. Each result includes service_agreement_url from forms_org_admin if configured.