[Bugfix] Fix ascend config for qwen3-next

[zhangxinyuehfad]

What this PR does / why we need it?

fix ascend config for qwen3-next about #3291

Does this PR introduce any user-facing change?

How was this patch tested?

• vLLM version: v0.11.0rc3
• vLLM main: vllm-project/vllm@releases/v0.11.0

[github-actions]

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[gemini-code-assist]

Code Review

This pull request aims to fix an issue with the Ascend configuration for qwen3-next models. The changes introduce a try-except block to safely retrieve the Ascend configuration, preventing a potential RuntimeError. It also updates how attention-related flags are passed. However, I've identified a critical issue where the logical relationship between use_sfa and use_mla appears to be broken by the changes, potentially leading to incorrect behavior. My review includes a comment with a suggested fix for this issue.