feat(checks): add parallel scenario execution to Suite.run

[harsh21234i]

Closes #2471

Summary

• add a parallel: bool = False flag to Suite.run()
• run scenarios concurrently with asyncio.TaskGroup when parallel=True
• preserve result order to match scenario order
• include the parallel flag in checks_suite_run_started and checks_suite_run_finished telemetry properties

Behavior

• default behavior is unchanged: suite.run() still runs serially
• suite.run(parallel=True) runs scenarios concurrently
• when return_exception=False, parallel execution fails fast and cancels sibling tasks if one scenario raises
• when return_exception=True, scenario-level exception handling is preserved through scenario.run(...)

Testing

• uv run -m pytest -q libs/giskard-checks/tests/core/test_suite.py
• uv run ruff check libs/giskard-checks/src/giskard/checks/scenarios/suite.py libs/giskard-checks/tests/core/test_suite.py

[gemini-code-assist]

Code Review

This pull request introduces parallel execution for scenario suites using asyncio.TaskGroup, allowing users to run scenarios concurrently while maintaining result order. The changes include updates to the Suite.run method, telemetry tracking for the new parallel flag, and a suite of tests verifying performance gains and error handling. Feedback from the review suggests centralizing the telemetry property logic, adopting list comprehensions for more idiomatic code, and implementing a concurrency limit using a semaphore to avoid resource exhaustion during large-scale parallel execution.

[kevinmessiaen]

Thanks for your PR, looking good, a few comments.

Formatting is broken, make sure to fix by running make format

[harsh21234i]

Updated the PR.

I fixed the parallel=True exception behavior so the common single-failure case re-raises the original exception
instead of surfacing a raw ExceptionGroup, and I also formatted the touched files.

make format is not available in my current Windows environment, so I ran the formatter directly with uv run ruff format on the changed files instead, then verified with ruff check and the focused suite tests.

Checks run:

• uv run ruff format libs/giskard-checks/src/giskard/checks/scenarios/suite.py libs/giskard-checks/tests/core/ test_suite.py
• uv run ruff check libs/giskard-checks/src/giskard/checks/scenarios/suite.py libs/giskard-checks/tests/core/ test_suite.py
• uv run -m pytest -q libs/giskard-checks/tests/core/test_suite.py

[kevinmessiaen]

Thanks for your contribution @harsh21234i

I've refactored a bit the run method to have two separate methods for sequential/parallel