Fix bug of refactoring TopKOutput in w4afp8 (#8745)

Co-authored-by: luoyuan.luo <luoyuan.luo@antgroup.com>

python/sglang/srt/layers/quantization/w4afp8.py

@@ -282,7 +282,7 @@ class W4AFp8MoEMethod(FusedMoEMethodBase):
         # TODO(ch-wan): move it out of this class
         from sglang.srt.layers.moe.cutlass_w4a8_moe import cutlass_w4a8_moe
 
-        topk_ids, topk_weights, _ = topk_output
+        topk_weights, topk_ids, _ = topk_output
         local_topk_ids = topk_ids
         if layer.expert_map is not None:
             "Translate info from expert_map to topk_ids"