[Feat][SP] Suport SP for VL MoE models (#7044)

### What this PR does / why we need it?

2nd PR for https://github.com/vllm-project/vllm-ascend/issues/5712,
extend SP to VL MoE models.


### Does this PR introduce _any_ user-facing change?
remove `sp_threshold` in additional config and reuse `sp_min_token_num`
from vLLM.


### How was this patch tested?
- Model: Qwen3-VL-30B-A3B, 
- TP4 DP2
- 100 reqs
- max concurrency 1

| Seq length | Mean TTFT (ms) main | Mean TTFT (ms) this PR |
|------------|---------------------|------------------------|
| 4k         | 429.40               | 323.3                  |
| 16k        | 1297.01              | 911.74                |

- vLLM version: v0.16.0
- vLLM main:
4034c3d32e

---------

Signed-off-by: realliujiaxu <realliujiaxu@163.com>

vllm_ascend/worker/model_runner_v1.py

@@ -1846,7 +1846,7 @@ class NPUModelRunner(GPUModelRunner):
         # Pad tokens to multiple of tensor_parallel_size when
         # enabled collective fusion for SP
         tp_size = self.vllm_config.parallel_config.tensor_parallel_size
-        if enable_sp(self.vllm_config) or enable_sp_by_pass(self.vllm_config):
+        if enable_sp(self.vllm_config) or enable_sp_by_pass():
             return round_up(num_scheduled_tokens, tp_size)
         return num_scheduled_tokens