Fix bug in parsing SecurityIdentifier
Fix bug in parsing SecurityIdentifier

This bug was introduced in PR #934

kaffeebrauer/Lean,jameschch/Lean,young-zhang/Lean,AlexCatarino/Lean,StefanoRaggi/Lean,JKarathiya/Lean,redmeros/Lean,tomhunter-gh/Lean,jameschch/Lean,StefanoRaggi/Lean,young-zhang/Lean,StefanoRaggi/Lean,StefanoRaggi/Lean,AnshulYADAV007/Lean,QuantConnect/Lean,redmeros/Lean,young-zhang/Lean,StefanoRaggi/Lean,JKarathiya/Lean,jameschch/Lean,Jay-Jay-D/LeanSTP,AnshulYADAV007/Lean,QuantConnect/Lean,Jay-Jay-D/LeanSTP,andrewhart098/Lean,Mendelone/forex_trading,AlexCatarino/Lean,jameschch/Lean,kaffeebrauer/Lean,tomhunter-gh/Lean,tomhunter-gh/Lean,Jay-Jay-D/LeanSTP,Jay-Jay-D/LeanSTP,AnshulYADAV007/Lean,Jay-Jay-D/LeanSTP,JKarathiya/Lean,jameschch/Lean,JKarathiya/Lean,AnshulYADAV007/Lean,kaffeebrauer/Lean,QuantConnect/Lean,Mendelone/forex_trading,young-zhang/Lean,kaffeebrauer/Lean,AnshulYADAV007/Lean,QuantConnect/Lean,andrewhart098/Lean,andrewhart098/Lean,Mendelone/forex_trading,andrewhart098/Lean,tomhunter-gh/Lean,kaffeebrauer/Lean,redmeros/Lean,redmeros/Lean,AlexCatarino/Lean,Mendelone/forex_trading,AlexCatarino/Lean