[MoE] [Refactor] Combine common_fused_moe and fused_moe (#3176)

### What this PR does / why we need it?
1. Move additional functionalities from fused_moe.py to
common_fused_moe.py and remove fused_moe.py
2. Remove unnecessary custom classes from qwen3_moe.py, and it will be
completely removed after we release vllm-ascend v0.11.0

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?

Qwen3-30B-A3B/Qwen3-30B-A3B-W8A8/DeepSeek-V3-W4A8-Pruing/deepseek-mtp/pangu-pro-moe-pruing:

1. Enable/Disable EP
3. Aclgraph & eager
4. SP


- vLLM version: v0.11.0

---------

Signed-off-by: Pr0Wh1teGivee <calvin_zhu0210@outlook.com>
Co-authored-by: weijinqian0 <12153182+weijinqian0@users.noreply.github.com>

vllm_ascend/torchair/models/qwen3_moe.py

@@ -53,9 +53,9 @@ from vllm.sequence import IntermediateTensors
 
 from vllm_ascend.ascend_config import get_ascend_config
 from vllm_ascend.attention.attention_v1 import AscendAttentionState
-from vllm_ascend.ops.fused_moe import AscendFusedMoE
 from vllm_ascend.torchair.ops.sequence_parallel import (MetadataForPadding,
                                                         init_metadata_for_sp)
+from vllm_ascend.torchair.ops.torchair_fused_moe import TorchairAscendFusedMoE
 
 
 class CustomSparseMoeBlock(Qwen3MoeSparseMoeBlock):
@@ -81,7 +81,7 @@ class CustomSparseMoeBlock(Qwen3MoeSparseMoeBlock):
             prefix=f"{prefix}.gate",
         )
 
-        self.experts = AscendFusedMoE(
+        self.experts = TorchairAscendFusedMoE(
             num_experts=config.num_experts,
             top_k=config.num_experts_per_tok,
             hidden_size=config.hidden_size,