Fix return type of sampleHeightMostDetailed function
Fix return type of sampleHeightMostDetailed function

CesiumGS/cesium,likangning93/cesium,likangning93/cesium,CesiumGS/cesium,AnalyticalGraphicsInc/cesium,progsung/cesium,likangning93/cesium,AnalyticalGraphicsInc/cesium,likangning93/cesium,CesiumGS/cesium,likangning93/cesium,CesiumGS/cesium,progsung/cesium,CesiumGS/cesium