Remove redundant assertion in health check test

Author: Abdul-Microsoft

src/tests/backend/test_app.py

@@ -324,5 +324,3 @@ def test_health_check_middleware_configured():
     """Test that health check middleware is in the middleware stack."""
     # The middleware should be present
     assert len(app.user_middleware) >= 2  # CORS + HealthCheck minimum
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