[Model] Support quantization of Qwen2VisionTransformer for Qwen2-VL

[mgoin]

Relies on #9812

Allows us to support quantization of the vision encoder for Qwen2-VL, where before we could only quantize the language model

Tested with

• nm-testing/Qwen2-VL-7B-Instruct-FP8-dynamic (only Qwen2Model quantized)
• nm-testing/Qwen2-VL-7B-Instruct-FP8-dynamic-all (Qwen2Model and Qwen2VisionTransformer quantized, just not lm_head)

[github-actions]

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[ywang96]

Thanks for adding support for quantization for this model!

[renjie0]

How much gain do you observe