[Bugfix] Fix Qwen3-VL regression from #24982

[ywang96]

Purpose

#24982 caused a regression since the Qwen3-VL needs to access the text config of Qwen3-MoE via get_text_config()

Test Plan

Test Result

Tested locally to make sure both Qwen3-VL and Qwen3-MoE can load properly.

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• The purpose of the PR, such as "Fix some issue (link existing issues this PR will resolve)".
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[gemini-code-assist]

Code Review

This pull request aims to fix a regression for Qwen3-VL by ensuring the text model configuration is used. The change replaces vllm_config.model_config.hf_config with vllm_config.model_config.hf_config.get_text_config(). While this fixes the issue for the multimodal Qwen3-VL model, it will likely cause a regression for the standalone Qwen3-MoE model, as the Hugging Face configuration for a non-multimodal model typically does not have a get_text_config() method, which would lead to an AttributeError. I've suggested a more robust fix in the comments, which is to use vllm_config.model_config.hf_text_config. This attribute is correctly populated by vLLM's ModelConfig to handle both multimodal and text-only models. This change should be applied to all instances, including the one in Qwen3MoeModel.__init__ which is not part of this PR's diff but contains the same pattern.