Remove unused row_idx in token_dispatcher (#3442)

### What this PR does / why we need it?
The `row_idx` parameter is no longer used since
PR[#2689](https://github.com/vllm-project/vllm-ascend/pull/2689), so
remove it across multiple files to remove unnecessary calculations and
parameter passing.

### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
accuracy test passed for Qwen3 235B and DeepSeek V3 671B after this PR.


- vLLM version: v0.11.0rc3
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0

---------

Signed-off-by: CaranLic <740821011@qq.com>

tests/ut/ops/test_moe_comm_method.py

@@ -204,7 +204,6 @@ class TestMoECommMethod(TestBase):
         topk_weights = torch.tensor([[0.5, 0.5], [0.3, 0.7], [0.8, 0.2],
                                      [0.6, 0.4]])
         topk_ids = torch.tensor([[0, 1], [1, 2], [2, 0], [1, 1]])
-        row_idx = torch.arange(4)
 
         # Make sure tensors are contiguous and have correct strides
         hidden_states = hidden_states.contiguous()
@@ -216,7 +215,6 @@ class TestMoECommMethod(TestBase):
                                          w2=w2,
                                          topk_weights=topk_weights,
                                          topk_ids=topk_ids,
-                                         row_idx=row_idx,
                                          activation="silu")
 
         # Verify result shape