Backport PR #19227 on branch v7.2.x (RFC: Replace np.char.decode with np.strings.decode) - #19229

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@pllim - I don't quite recall when np.strings was introduced, but fear this may fail here since we still support numpy < 2... If so, I'd suggest to just silence the deprecation warning rather than introduce numpy-version specific paths.

Whoops, approved prematurely...
numpy.strings was indeed not available until version 2.0, so I agree this backport isn't viable. Maybe we should also add an upper bound on numpy for the backport branch too

superseded by #19233

Thanks, all!