[Misc] Fix Current vLLM config is not set. warnings, assert to avoid issues in the future (#31747)

Signed-off-by: Lucas Wilkinson <lwilkins@redhat.com>
Signed-off-by: Lucas Wilkinson <LucasWilkinson@users.noreply.github.com>
Co-authored-by: Luka Govedič <ProExpertProg@users.noreply.github.com>

tests/kernels/quantization/test_silu_mul_nvfp4_quant.py

@@ -31,6 +31,7 @@ BLOCK_SIZE = 16
 @pytest.mark.parametrize("shape", SHAPES)
 @torch.inference_mode()
 def test_silu_mul_nvfp4_quant(
+    default_vllm_config,
     dtype: torch.dtype,
     shape: tuple[int, int],
 ) -> None: