fix conversion for text embeddings for fp16 models

[eaidova]

What does this PR do?

text embedding part in vlm models if original model loaded in bf16/fp16 without that changes exported in onnx due to overriding input signature by openvino pytorch frontend

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• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you make sure to update the documentation with your changes?
• Did you write any new necessary tests?

[HuggingFaceDocBuilderDev]

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