bugfix: python-babel tests fail when not UTC around Eastern Daylight time

[s1341]

See python-babel/babel#988 on upstream

Description of changes

• exported TZ=UTC for checkPhase
• added pytz to nativeCheckInputs
• disabled the test_format_time test

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.05 Release Notes (or backporting 22.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[SuperSandro2000]

Please follow the contributing guide when naming your commits.

---

This PR rebuilds a lot of packages which means we must target staging. Please follow the contributing guide to not potentially ping a lot of people.

[SuperSandro2000]

Do we also want to add it at runtime if zoneinfo not always works?

https://github.com/python-babel/babel/blob/master/setup.py#L64-L68

[s1341]

Closing as this is already fixed on staging: a9b7d738fc14