Refactor: rename reflectivity to intensity in LiDAR point cloud data

- Update LiDAR point structure definitions in ObTypes.h
- Rename reflectivity field to intensity in OBLiDARPoint and OBLiDARSpherePoint structures
- Update point cloud field names and iterators in ob_lidar_node.cpp
- Modify Chinese documentation to reflect the terminology change
- Ensure consistency across all LiDAR data publishing methods

This change aligns the codebase with standard LiDAR terminology where
'intensity' is the commonly used term for describing the strength of
the laser return signal.

orbbec_camera/SDK/include/libobsensor/h/ObTypes.h

@@ -837,7 +837,7 @@ typedef struct {
     float   x;             ///< X coordinate, unit mm
     float   y;             ///< Y coordinate, unit mm
     float   z;             ///< Z coordinate, unit mm
-    uint8_t reflectivity;  ///< reflectivity
+    uint8_t intensity;  ///< intensity
     uint8_t tag;           ///< point state
 } OBLiDARPoint, ob_lidar_point;
 
@@ -848,7 +848,7 @@ typedef struct {
     float   distance;      ///< distance, unit: mm
     float   theta;         ///< azimuth angle, unit: degrees
     float   phi;           ///< zenith angle, unit: degrees
-    uint8_t reflectivity;  ///< reflectivity
+    uint8_t intensity;  ///< intensity
     uint8_t tag;           ///< tag
 } OBLiDARSpherePoint, ob_lidar_sphere_point;