ggsn,pgw: Expect Multiple-Services-Indicator AVP in Initial CCR

Multiple-Services-Indicator AVP is only meant to be sent in CCR Init.
Let's not expect it in Update nor in Termination CCR, open5gs stopped
sending it there recently in 9948fba05afb8e1b118f0c29a84ffe38c0f21b75.

Change-Id: Ic4d6be4bf28c65817ce912a8be10937db0b5dba9
2 files changed