Fix Qwen3.5 model config metadata parsing

[csg-pr-bot]

Summary:

• Updated model config parsing logic to handle Qwen3.5's nested structure, where fields like num_hidden_layers and hidden_size are now located inside text_config instead of the root level.
• Ensures compatibility with the new Qwen3.5 architecture by correctly extracting parameters from the nested text_config and vision_config objects.

[csg-pr-bot]

Depends on #1186

[HaiHui886]

lgtm