Handle target DU UE context setup when handover preparation info
is unavailable (i.e. re-establishment scenario) by retrieving
secondary UE ID from F1 UE data.
rrc_f1_ue_context_setup_for_target_du is either applying to
handover or re-establishment. In the latter scenario, populate
DU UE ID, which should be known.
Guido Casati
ebc9158ca4