Follow-up on Pillow's mode argument in Image.fromarray()

PR #9150 fixed Issue #9135. The issue is that Pillow deprecated the mode parameter in Image.fromarray(): https://pillow.readthedocs.io/en/stable/releasenotes/11.3.0.html#image-fromarray-mode-parameter. Also see the Pillow PR that implements the change for more discussion: https://github.com/python-pillow/Pillow/pull/9018

However, we depend on the old behavior. PR #9150 implements an ugly hack to mitigate the removal of the old behavior. Pillow PR https://github.com/python-pillow/Pillow/pull/9063 partially restores the mode parameter. When it is part of a release, we should evaluate if we can go back to using the mode parameter in Image.fromarray() and avoid our ugly hack.