[Refactor] [SP]The sequence parallelism characteristics in the MoE and Dense models are integrated into a single solution. (#3085)

What this PR does / why we need it?

there are two sets of sp implementations for moe and dense models. One
is called sequence_parallelism, and the other is flashcomm_v1.
We did the following things：

Merge two sets of code with the same implementation into one.
Remove the implementation of sequence_parallelism, as this solution
cannot support aclgraph.
Does this PR introduce any user-facing change?

No

How was this patch tested?

e2e&ut

- vLLM version: v0.10.2
- vLLM main:
f225ea7dd9

---------

Signed-off-by: weijinqian_v1 <weijinqian@huawei.com>
Co-authored-by: weijinqian_v1 <weijinqian@huawei.com>

vllm_ascend/platform.py

@@ -282,12 +282,6 @@ class NPUPlatform(Platform):
                 ascend_config.ascend_scheduler_config)
             vllm_config.scheduler_config = ascend_scheduler_config
 
-        if compilation_config.pass_config.enable_sequence_parallelism:
-            if not parallel_config.enable_expert_parallel or vllm_config.model_config.hf_config.model_type != "qwen3_moe":
-                raise NotImplementedError(
-                    "For better performance in Qwen3 MoE, SP only works exclusively with MC2, AllToAll, and AllToAllV."
-                )
-
     @classmethod
     def get_attn_backend_cls(cls,
                              selected_backend,