Add support for quantized qwen2-0.5b

[bil-ash]

This PR adds support for quantized(q4f16_1) qwen2-0.5b. Solves issue . PR must be merged before merging this.
@Neet-Nestor

[Neet-Nestor]

Unfortunately, this won't fix the issue since the model Qwen2-0.5B-Instruct-q4f16-MLC you added is not available in WebLLM yet. Instead we need to compile the model, upload to huggingface, update WebLLM, and finally update our app.

[bil-ash]

Unfortunately, this won't fix the issue since the model Qwen2-0.5B-Instruct-q4f16-MLC you added is not available in WebLLM yet. Instead we need to compile the model, upload to huggingface, update WebLLM, and finally update our app.

I saw that and so I have also created the required PR in the web-llm repo.

[Neet-Nestor]

Thanks! Let me try.

[Neet-Nestor]

Thanks! It's working perfectly on my end. I will leave the other 2 PRs for my team to review, but I can merge this one and publish a new version of the webapp so that you can use it immediately.