Update IEXDataQueueHandler.cs
Update IEXDataQueueHandler.cs

Fixes the previous check for null data, which failed to catch null open prices

QuantConnect/Lean,jameschch/Lean,StefanoRaggi/Lean,AlexCatarino/Lean,JKarathiya/Lean,StefanoRaggi/Lean,JKarathiya/Lean,AlexCatarino/Lean,AlexCatarino/Lean,jameschch/Lean,StefanoRaggi/Lean,jameschch/Lean,JKarathiya/Lean,QuantConnect/Lean,JKarathiya/Lean,StefanoRaggi/Lean,jameschch/Lean,QuantConnect/Lean,AlexCatarino/Lean,jameschch/Lean,QuantConnect/Lean,StefanoRaggi/Lean