BUG: avoid soon-to-be-deprecated direct mutations of ndarray.shape attributes (1/2)

[neutrinoceros]

PR Summary

xref: numpy/numpy#29536

This is incomplete at the time of opening, I just want to take what I already have for a spin on CI

PR Checklist

• New features are documented, with docstrings and narrative docs
• Adds a test for any bugs fixed. Adds tests for new features.

[matthewturk]

Your work on making this backward- and forward-compatible is admirable, and I wish it didn't have to be so.

[neutrinoceros]

yeah it's a bit fiddly. Hopefully it should be straightforward to find-and-replace when the time comes.

[matthewturk]

What I was trying to say without saying it is that I wish we didn't have to make this change, and I agree it looks a bit fiddly to use the COPY object etc, but I guess we have to because of upstream changes. So, thank you.

[neutrinoceros]

Oh yeah, this has been on my radar for a while but I was constantly putting it off, but it seems to be moving forward upstream...

[neutrinoceros]

Clearly I messed up somewhere. Help is welcome, but in the meantime, I'll be off duty for today.

[neutrinoceros]

ok this is now reasonably stable, so, opening for review.
Note that I avoided dealing with yt/volume_rendering to save whatever little time, but this needs to be done too (preferably by someone else, that I can then review).

[neutrinoceros]

... I couldn't resist. Volume Rendering is now handled in its own PR to hopefully make reviewing swifter. See #5309