Can niriss_bounding_box be removed?

[emolter]

Working on updating the assign_wcs step for code style, I noticed that assign_wcs.niriss.niriss_bounding_box is not used anywhere in the pipeline. Is this being used outside the pipeline, or can it be removed? If it can be removed, is a deprecation period appropriate? (It is not in the __all__ of that file).

[tapastro]

Looks like it was added for https://jira.stsci.edu/browse/JP-2153, which lists some test branches. Perhaps @nden could speak to whether there was a long-term integration plan that was lost to time, or if we can simply remove it.