Update Z charm inclusive decfile eventtype
When making lhcb-simulation/mc-requests!350 (merged), it was discovered that this pipeline ran when it shouldn't, given that !1686 (merged) was merged but the new decfile version hasn't been released.
Turns out that when searching for the eventtype, the eventtype has been used by the other decfile.
This merge request changes the eventtype from @kefarmer's request to something thats free, to keep things unique