Reinstate best_of for V0 (#14356)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

tests/v1/sample/test_sampling_params_e2e.py

@@ -25,6 +25,14 @@ def test_n_gt_1(model):
     assert len(outputs[0].outputs) == 3
 
 
+def test_best_of(model):
+    """Raise a ValueError since best_of is deprecated."""
+
+    params = SamplingParams(n=2, best_of=3)
+    with pytest.raises(ValueError):
+        _ = model.generate(PROMPT, params)
+
+
 def test_penalties(model):
     """Check that we do not get errors if applied."""