mme: Take into account KSI update by NetworkSince recently, open5gs updates the KSI received from the UE in order tocomply better with 4G Core expectancies.Track assigned KSI in ttcn3 code and update it according toexpectancies.Depends: open5gs.git 70310979c58fe186e9eaa06bec9d9a31f24ff7a1Change-Id: Ie97788c5d9996370cd3e24cc0ff7c003adff1a65