Fix: step.altNrql is optional

[aminoz007]

check if step.altNrql has values since it is optional and compare to stat.value.eventName not stat.value.nrql.eventName

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}