Add nodask constraint for test-py313-no-dask environment

[weiji14]

Description

Explicitly exclude dask-core from being installed. Discovered that some dask-dependent tests were being ran in the no-dask environment in PR #11383.

Reference: https://pixi.prefix.dev/latest/reference/pixi_manifest/#constraints

Checklist

• Patches small changes to the pixi env definitions #10976
• Tests added
• User visible changes (including notable bug fixes) are documented in whats-new.rst
• New functions/methods are listed in api.rst

AI Disclosure

[weiji14]

Removed iris from feature.extras.dependencies because it depends on dask, and was polluting the test-py313-no-dask environment.

Error:   × failed to solve requirements of environment 'test-py313-no-dask' for platform 'win-64'
  ├─▶   × failed to solve the environment

  ╰─▶ Cannot solve the request because of: iris * cannot be installed because there are no viable options:
      ├─ iris 2.4.0 | 2.4.0 | 2.4.0 | 2.4.0 | 3.0.0 | 3.0.0 | 3.0.0 | 3.0.0 | 3.0.1 | 3.0.1 | 3.0.1 | 3.0.1 | 3.0.1 | 3.0.1 | 3.0.1 | 3.0.1 | 3.0.2 | 3.0.2 | 3.0.2 | 3.0.2 | 3.0.2 | 3.0.2 | 3.0.2 | 3.0.2 | 3.0.2 | 3.0.2 | 3.0.2 | 3.0.2 | 3.0.3 | 3.0.3 | 3.0.3 | 3.0.3 | 3.0.4 | 3.0.4 | 3.0.4 | 3.1.0 | 3.1.0 | 3.1.0 | 3.1.0 | 3.1.0 | 3.1.0 | 3.1.0 would require
      │  └─ dask >=2, which cannot be installed because there are no viable options:
      │     └─ dask 2.0.0 | 2.1.0 | 2.2.0 | 2.3.0 | 2.4.0 | 2.5.0 | 2.5.2 | 2.6.0 | 2.7.0 | 2.8.0 | 2.8.1 | 2.9.0 | 2.9.1 | 2.9.2 | 2.10.0 | 2.10.1 | 2.11.0 | 2.12.0 | 2.13.0 | 2.14.0 | 2.15.0 | 2.16.0 | 2.17.0 | 2.17.1 | 2.17.2 | 2.18.0 | 2.18.1 | 2.19.0 | 2.20.0 | 2.21.0 | 2.22.0 | 2.23.0 | 2.24.0 | 2.25.0 | 2.26.0 | 2.27.0 | 2.28.0 | 2.29.0 | 2.30.0 | 2020.12.0 | 2021.1.0 | 2021.1.1 | 2021.2.0 | 2021.3.0 | 2021.3.1 | 2021.4.0 | 2021.4.1 | 2021.5.0 | 2021.5.1 | 2021.6.0 | 2021.6.1 | 2021.6.2 | 2021.7.0 | 2021.7.1 | 2021.7.2 | 2021.8.0 | 2021.8.1 | 2021.9.0 | 2021.9.1 | 2021.10.0 | 2021.11.0 | 2021.11.1 | 2021.11.2 | 2021.12.0 | 2022.1.0 | 2022.1.1 | 2022.2.0 | 2022.2.1 | 2022.3.0 | 2022.3.0 | 2022.4.0 | 2022.4.1 | 2022.4.2 | 2022.5.0 | 2022.5.1 | 2022.5.2 | 2022.6.0 | 2022.6.1 | 2022.7.0 | 2022.7.1 | 2022.8.0 | 2022.8.0 | 2022.8.0 | 2022.8.1 | 2022.9.0 | 2022.9.1 | 2022.9.2 | 2022.10.0 | 2022.10.0 | 2022.10.0 | 2022.10.2 | 2022.11.0 | 2022.11.1 | 2022.12.0 | 2022.12.1 | 2023.1.0 | 2023.1.1 | 2023.2.0 | 2023.2.1 | 2023.3.0 | 2023.3.1 | 2023.3.2 | 2023.4.0 | 2023.4.1 | 2023.5.0 | 2023.5.1 | 2023.6.0 | 2023.6.1 | 2023.7.0 | 2023.7.1 | 2023.8.0 | 2023.8.1 | 2023.9.0 | 2023.9.1 | 2023.9.2 | 2023.9.3 | 2023.10.0 | 2023.10.1 | 2023.11.0 | 2023.12.0 | 2023.12.1 | 2024.1.0 | 2024.1.1 | 2024.2.0 | 2024.2.1 | 2024.3.0 | 2024.3.0 | 2024.3.1 | 2024.4.0 | 2024.4.1 | 2024.4.2 | 2024.5.0 | 2024.5.1 | 2024.5.2 | 2024.6.0 | 2024.6.2 | 2024.7.0 | 2024.7.1 | 2024.8.0 | 2024.8.1 | 2024.8.2 | 2024.9.0 | 2024.9.1 | 2024.10.0 | 2024.11.0 | 2024.11.1 | 2024.11.2 | 2024.11.2 | 2024.12.0 | 2024.12.1 | 2025.1.0 | 2025.2.0 | 2025.3.0 | 2025.3.1 | 2025.4.0 | 2025.4.1 | 2025.5.0 | 2025.5.1 | 2025.5.1 | 2025.7.0 | 2025.9.0 | 2025.9.1 | 2025.9.2 | 2025.10.0 | 2025.11.0 | 2025.12.0 | 2026.1.1 | 2026.1.2 | 2026.1.2 | 2026.3.0 | 2026.6.0 would require
      │        └─ dask-core 2.0.0.*, for which no candidates were found.

This might reduce test coverage on iris-dependent tests though, so someone should verify if this makes sense.

[weiji14]

Should this be renamed to test-py312-..., or should the py312 feature be py313 instead? Maybe doesn't matter if #11377 goes ahead.