Re-enable reliable streaming integration tests

Remove the hard skip on test_03_reliable_streaming tests that was
temporarily disabled for instability investigation. CI infrastructure
(Azurite, DTS emulator, Redis, func CLI) is already in place.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

python/packages/azurefunctions/tests/integration_tests/test_03_reliable_streaming.py

@@ -26,7 +26,6 @@ pytestmark = [
     pytest.mark.integration,
     pytest.mark.sample("03_reliable_streaming"),
     pytest.mark.usefixtures("function_app_for_test"),
-    pytest.mark.skip(reason="Temp disabled to fix test instability - needs investigation into root cause"),
 ]