[Bugfix] FlashInfer MXINT4 MoE crashes, missing do_finalize (#39315)

Signed-off-by: Benjamin Chislett <bchislett@nvidia.com>
Signed-off-by: Benjamin Chislett <chislett.ben@gmail.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

vllm/model_executor/layers/quantization/utils/flashinfer_mxint4_moe.py

@@ -259,8 +259,12 @@ def flashinfer_trtllm_mxint4_moe(
         routed_scaling_factor=None,
         routing_method_type=routing_method_type,
         enable_pdl=None,
+        do_finalize=True,
         output=None,
         tune_max_num_tokens=8192,
-    ).to(x.dtype)
+    )
+    if isinstance(out, (tuple, list)):
+        out = out[0]
+    out = out.to(x.dtype)
 
     return out