DataSource Parameter should be mandatory in the test PIXv3_CLIENT

Spec (page 42) : https://www.e-health-suisse.ch/fileadmin/user_upload/Dokumente/2019/E/190528_Entwurf_EPDV-EDI_Anhang_5_E1_V1.9_e.pdf

"The DataSource Parameter MUST be specified to the assigning authority/authorities of the MPI-PID in the affinity domain. No other assigning authority/authorities MUST be used. See also ITI TF-2b, chapter 3.45.4.1.2.1"