[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/models/deepseek_v2.py

@@ -62,7 +62,7 @@ from vllm_ascend.ascend_config import get_ascend_config
 from vllm_ascend.models.layers.mla import AscendMLAModules
 from vllm_ascend.models.layers.sfa import (AscendSFAModules,
                                            AscendSparseFlashAttention, Indexer)
-from vllm_ascend.ops.fused_moe import AscendFusedMoE
+from vllm_ascend.ops.common_fused_moe import AscendFusedMoE
 
 
 class CustomDeepseekV2RowParallelLinear(RowParallelLinear):