Seems like a bug after colmap format exportation

I use `export_format="colmap-gs_ply-gs_video"` sequence to produce both colmap and PLY, finding out that the intrinsic values will change after colmap files generation.
In line 65-66 (_src/depth_anything_3/utils/export/colmap.py_)
```
intrinsic[:1] *= orig_w / w
intrinsic[1:2] *= orig_h / h
```
Should not use self multiplication here, or make a copy in line 63 `intrinsic = prediction.intrinsics[fidx].copy()`, otherwise the gs video will show bad result.