### What this PR does / why we need it?
Qwen3.5 Moe supports enabling the dispatch_ffn_combine fusion operator.
Fix problem: In the w8a8 quantization scene, Qwen3.5 model's config.json
lacks the quantize field. The previous logic strictly relied on
quant_type == "w8a8_dynamic" to enable VLLM_ASCEND_ENABLE_FUSED_MC2.
This caused the dispatch_ffn_combine fusion operator to fail to activate
even when the environment variable was set.
Enable dispatch_ffn_combine fusion operator for BF16 scenarios.
- vLLM version: v0.16.0
- vLLM main:
4034c3d32e
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Signed-off-by: asunxiao <asunxiao@qq.com>