[BugFix]fix handle 4 return values from noaux_tc_redundant op (#6384)

* fix: handle 4 return values from noaux_tc_redundant op

The noaux_tc_redundant CUDA op is defined with 4 outputs in PD_BUILD_STATIC_OP:
- output_tensor (scores)
- topk_values
- topk_indices
- tokens_per_expert_stats_list_out (inplace updated)

The Python code was only unpacking 3 values, causing:
  ValueError: too many values to unpack (expected 3)

This fix correctly unpacks all 4 return values, ignoring the inplace
updated tensor which is the same as the input tokens_per_expert_stats_list.

Co-Authored-By: Claude (Claude Opus 4.5) <noreply@anthropic.com>

* fix: make noaux_tc_redundant return 4 values to match OP definition

The PD_BUILD_STATIC_OP defines 4 outputs but the function only returned 3,
causing inconsistent behavior across different Paddle framework versions.

This fix explicitly returns 4 values:
- scores (inplace modified)
- topk_values
- topk_indices
- tokens_per_expert_stats_list (inplace modified via atomicAdd)

Co-Authored-By: Claude (Claude Opus 4.5) <noreply@anthropic.com>

---------

Co-authored-by: Claude (Claude Opus 4.5) <noreply@anthropic.com>

custom_ops/gpu_ops/noaux_tc_redundant.cu

@@ -61,7 +61,8 @@ std::vector<paddle::Tensor> NoauxTcRedundant(
       redundant_ep_rank_num_plus_one,
       stream);
 
-  return {scores, topk_values, topk_indices};
+  // Return 4 values to match PD_BUILD_STATIC_OP Outputs definition
+  return {scores, topk_values, topk_indices, tokens_per_expert_stats_list};
 }
 
 std::vector<paddle::DataType> NoauxTcRedundantInferDtype(