Improve support for imagecodecs in VirtualiZarr

[maxrjones]

• Debug issues using the sharding codec with the GPU buffer (Add more unit tests for GPU buffer zarr-developers/zarr-python#2978)
• Wait for support of unsigned bytes in Zarr-Python (Use unsigned bytes to back Buffer zarr-developers/zarr-python#2738)
• Submit a PR upstream in either imagecodecs or numcodecs with imagecodecs wrapper for Zarr V3 metadata (https://github.com/maxrjones/virtual-tiff/blob/main/src/virtual_tiff/imagecodecs.py)