ci: set UV_NO_SYNC to avoid implicit syncs with uv run

[rg936672]

PR Type

• Bugfix
• CI related changes

Description

This ensures the environment is exactly as we specify in the uv sync.

How Has This Been Tested?

Check log output - no extra packages are being installed.

Does this PR introduce a breaking change?

No.

Checklist before requesting a review

• I have made sure that my PR is not a duplicate.
• My code follows the style guidelines of this project.
• I have ensured my code is easy to understand, including docstrings and comments where necessary.
• I have performed a self-review of my code.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• New and existing unit tests pass locally with my changes.
• Any dependent changes have been merged and published in downstream modules.
• I have updated CHANGELOG.md, if appropriate.

[github-actions]

Performance review

Commit d5d0ffb - Merge 8eaa827 into 94a1a2d

No significant changes to performance.