fix: Install PyTest AsyncIO

[morgan-wowk]

Changes:

• Installs pytest-asyncio
  • Recently added tests (test_request_id_concurrency, test_instrumentation_request_middleware) require the pytest-asyncio package

Resolves:

CI test pipeline errors:

=================================== FAILURES ===================================
________________ test_contextvars_isolation_across_async_tasks _________________
async def functions are not natively supported.
You need to install a suitable plugin for your async framework, for example:
  - anyio
  - pytest-asyncio
  - pytest-tornasync
  - pytest-trio
  - pytest-twisted
=============================== warnings summary ===============================
tests/test_request_id_concurrency.py:165
  /home/runner/work/tangle/tangle/tests/test_request_id_concurrency.py:165: PytestUnknownMarkWarning: Unknown pytest.mark.asyncio - is this a typo?  You can register custom marks to avoid this warning - for details, see https://docs.pytest.org/en/stable/how-to/mark.html
    @pytest.mark.asyncio

tests/test_instrumentation_request_middleware.py: 10 warnings
tests/test_request_id_concurrency.py: 4 warnings
  /home/runner/work/_temp/setup-uv-cache/archive-v0/fp1ChoPUTudWUXi3EmdQL/lib/python3.13/site-packages/starlette/applications.py:192: DeprecationWarning: The `route` decorator is deprecated, and will be removed in version 1.0.0. Refer to https://www.starlette.io/routing/ for the recommended approach.
    warnings.warn(

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
- generated xml file: /home/runner/work/tangle/tangle/junit/test-results-3.13.xml -
=========================== short test summary info ============================
FAILED tests/test_request_id_concurrency.py::test_contextvars_isolation_across_async_tasks - Failed: async def functions are not natively supported.
You need to install a suitable plugin for your async framework, for example:
  - anyio
  - pytest-asyncio
  - pytest-tornasync
  - pytest-trio
  - pytest-twisted
================== 1 failed, 34 passed, 15 warnings in 2.38s ===================
Error: Process completed with exit code 1.