Enable Stryker.NET in CI

[kudima03]

Now that the issue stryker-mutator/stryker-net#3349 has been resolved, we should re-enable mutation testing in our CI pipeline.

Tasks:

• Re-enable Stryker.NET execution step in the CI workflow.
• Verify that the mutation tests run successfully and produce reports.
• Ensure that the build passes and reports are correctly published (if applicable).

Acceptance Criteria:

• Stryker step is active in CI again.
• CI passes without errors related to Stryker.
• Mutation testing results are available in the CI output or artifacts.