bug fixed: empty flights when position remains
bug fixed: empty flights when position remains

bug fixed: concerning heading/pitch/roll in 2d as well to not wrongly create an empty flight when camera position remains

fixes #3457
wallw-bits/cesium,kiselev-dv/cesium,progsung/cesium,esraerik/cesium,jason-crow/cesium,progsung/cesium,oterral/cesium,YonatanKra/cesium,NaderCHASER/cesium,ggetz/cesium,AnimatedRNG/cesium,emackey/cesium,ggetz/cesium,denverpierce/cesium,likangning93/cesium,denverpierce/cesium,jason-crow/cesium,wallw-bits/cesium,hodbauer/cesium,AnimatedRNG/cesium,esraerik/cesium,likangning93/cesium,likangning93/cesium,soceur/cesium,esraerik/cesium,hodbauer/cesium,wallw-bits/cesium,omh1280/cesium,YonatanKra/cesium,aelatgt/cesium,likangning93/cesium,denverpierce/cesium,jasonbeverage/cesium,AnalyticalGraphicsInc/cesium,esraerik/cesium,YonatanKra/cesium,CesiumGS/cesium,aelatgt/cesium,emackey/cesium,ggetz/cesium,omh1280/cesium,aelatgt/cesium,ggetz/cesium,emackey/cesium,emackey/cesium,CesiumGS/cesium,AnimatedRNG/cesium,josh-bernstein/cesium,omh1280/cesium,jason-crow/cesium,oterral/cesium,YonatanKra/cesium,oterral/cesium,likangning93/cesium,kiselev-dv/cesium,jason-crow/cesium,josh-bernstein/cesium,kaktus40/cesium,geoscan/cesium,CesiumGS/cesium,denverpierce/cesium,kaktus40/cesium,NaderCHASER/cesium,NaderCHASER/cesium,jasonbeverage/cesium,AnimatedRNG/cesium,soceur/cesium,AnalyticalGraphicsInc/cesium,wallw-bits/cesium,omh1280/cesium,kiselev-dv/cesium,aelatgt/cesium,CesiumGS/cesium,soceur/cesium,CesiumGS/cesium,hodbauer/cesium,geoscan/cesium,kiselev-dv/cesium