Correct dependencies in py-poetry, py-numexpr, and py-metpy packages

[climbfuji]

Description

• Bug fix in var/spack/repos/builtin/packages/py-poetry/package.py: specify ranges of py-xattr dependency on Darwin correctly to avoid concretization errors
• Bug fix in var/spack/repos/builtin/packages/py-numexpr/package.py: 2.8.4 doesn't build with py-numpy@1.26
• Add py-pint@0.19.2 and correct version dependency on py-pint in py-metpy

Upstream PR for spack develop for all of the above changes: https://github.com/spack/spack/pull/44651

Issue

Working towards https://github.com/JCSDA/spack-stack/issues/1122

Dependencies

None

Testing

See https://github.com/JCSDA/spack-stack/pull/1124

[climbfuji]

I'll merge this, if the review of the upstream PR to spack develop requires additional changes, I will bring them over in a follow-up PR.