Bump xunit (#42804)

Bumps the dotnet group in /docs/core/testing/snippets/order-unit-tests/csharp with 1 update: [xunit](https://github.com/xunit/xunit).


Updates `xunit` from 2.9.1 to 2.9.2
- [Commits](xunit/xunit@v2-2.9.1...v2-2.9.2)

---
updated-dependencies:
- dependency-name: xunit
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: dotnet
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]