python3Packages.typer: disable completion tests on all platforms

[risicle]

Description of changes

These were previously just failing on aarch64 but #174995 started to show them failing on x86_64 linux. It's possible this shellingham library just doesn't like doing its thing inside the nix build environment.

ZHF: #172160

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/)
• 22.05 Release Notes (or backporting 21.11 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
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[pbsds]

This PR fails to evaluate once merged on top of master:

error: undefined variable 'stdenv'

       at /home/pbsds/.cache/nixpkgs-review/pr-175034/nixpkgs/pkgs/development/python-modules/typer/default.nix:53:23:

           52|     "test_install_completion"
           53|   ] ++ lib.optionals (stdenv.isLinux && stdenv.isAarch64) [
             |                       ^
           54|     "test_install_completion"

Please rebase it

[risicle]

I think I'll close it instead as it would appear most people aren't having this problem (anymore?)