[Sampler] Adapt to FlashInfer 0.2.3 sampler API (#15777)

Signed-off-by: Bowen Wang <abmfy@icloud.com>
Co-authored-by: mgoin <mgoin64@gmail.com>

tests/samplers/test_sampler.py

@@ -647,6 +647,8 @@ def test_flashinfer_fallback(seed: int, device: str):
     if not envs.VLLM_USE_FLASHINFER_SAMPLER:
         pytest.skip("Flashinfer sampler is disabled")
 
+    pytest.skip("After FlashInfer 0.2.3, sampling will never fail")
+
     set_random_seed(seed)
     torch.set_default_device(device)
     batch_size = random.randint(1, 256)