[Bug]: RVIO removing any additional channels from EXR

### What happened?

Not sure if this is a bug or if there's something I might be overlooking.

When I am trying to process a .exr image/sequence with rvio the resulting output only contains RGBA channels any additional channels included in the source image are removed.

Here is an example image.
[example.zip](https://github.com/AcademySoftwareFoundation/OpenRV/files/11028222/example.zip)

This is the command I am using to process the image
`rvio example.exr -o example_out.exr -codec PIZ -outhalf`

I would expect to get the same image with only changed compression.

### List all the operating systems versions where this is happening

CentOS Linux release 7.9.2009

### On what computer hardware is this happening?

N/A

### Relevant console log output

_No response_

### Environment variables

_No response_

### Extra information

_No response_

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct

Start by reproducing the issue with the attached example.exr and the command `rvio example.exr -o example_out.exr -codec PIZ -outhalf`. Compare the source and output channel sets; done means the additional channels are preserved while the output compression changes.

Written by the indexing model from the issue text.