utils/flight-tracking: Remove unused "flight_display" variable
utils/flight-tracking: Remove unused "flight_display" variable

Harry-R/skylines,Harry-R/skylines,shadowoneau/skylines,Harry-R/skylines,skylines-project/skylines,Turbo87/skylines,Turbo87/skylines,RBE-Avionik/skylines,shadowoneau/skylines,kerel-fs/skylines,Turbo87/skylines,Harry-R/skylines,RBE-Avionik/skylines,skylines-project/skylines,kerel-fs/skylines,shadowoneau/skylines,RBE-Avionik/skylines,skylines-project/skylines,Turbo87/skylines,RBE-Avionik/skylines,kerel-fs/skylines,shadowoneau/skylines,skylines-project/skylines