Modified code for exporting eval pcd

[dongjae0107]

Hi :)

How about slightly modifying the logic in 'export_eval_pcd.cpp' that marks 'gt_point' as dynamic? Currently, with a voxel size of 0.1, if the 'nearest_point' in 'et_cloud' is farther than 0.05 (half of the voxel size), 'gt_point' is classified as dynamic. However, when using the voxel downsampling method, which marks the space that the voxel spans, a more accurate approach might be to check if 'gt_point' falls within the space that 'nearest_point' spans before marking gt_point as dynamic. This would improve the accuracy of the classification.