Fix for 14674: better check for integer pixel dimensions - #14676

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This isn't making tests pass because there are other parts of the codebase that cause the same deprecation warning. See https://github.com/astropy/astropy/actions/runs/4768953830/jobs/8478846216?pr=14676.

@pllim What would you like to do here? Maybe we could ignore the deprecation warning globally, but add an explicit check for it just in this module? Or would it be better just to integrate this PR into another one handling this warning everywhere?

Wow, that is crazy. Were we abusing numpy that badly?!

caused by numpy/numpy#10615

@saimn , what do you think? Should we blanket ignore or try to fix the 50+ failures before v5.3rc?

I already had a PR for this: #14671

@larrybradley , you plan to fix all of them? 👀

Not today!

@saimn , what do you think? Should we blanket ignore or try to fix the 50+ failures before v5.3rc?

I plan to do the rc end of next week so we have a bit of time. It's not critical since it's only Numpy dev but Numpy 1.25 is expected in June I guess so we will need to fix errors soon anyway.

Closing in favor of #14671