post https://api.medicys-conventionnel.fr/api/JudicialFile/AddApplicantParty
The property PartyType is read-only and so must not be provided.
The property IsCompany is true if the party is a legal entity. In this case,
the fields CompanyName and CompanyLegalName have to be filled.
If the party is a company, the party needs to have a key PublicId
which value is the unique identifier of the company regarding the country. In france it is the SIREN