ci: replace styfle/cancel-workflow-action with native concurrency cancel-in-progress

[Copilot]

Replaces the third-party styfle/cancel-workflow-action with GitHub Actions' built-in concurrency to cancel in-progress runs when a new one is triggered for the same ref.

Changes

• .github/workflows/check.yaml: Removed styfle/cancel-workflow-action@0.13.1 step from build_and_test job; added workflow-level concurrency block:

concurrency:
    group: ${{ github.workflow }}-${{ github.ref }}
    cancel-in-progress: true

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