Fix data model for gr.DataFrame

[abidlabs]

Closes: #6297

Test with:

import gradio as gr
import pandas as pd


def fn(df: pd.DataFrame) -> str:
    return df


df_orig = pd.DataFrame(data={"a": [1, 2, 3]})

with gr.Blocks() as demo:
    df = gr.Dataframe(value=df_orig, type="pandas")
    df2 = gr.Dataframe(value=df_orig, type="pandas")
    btn = gr.Button()

    btn.click(fn=fn, inputs=df, outputs=df2)

demo.launch()

or repro in original issue

[gradio-pr-bot]

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---

Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/35de9e0fa588c57d459b55eae4fc00f5eed929f1/gradio-4.1.1-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@35de9e0fa588c57d459b55eae4fc00f5eed929f1#subdirectory=client/python"

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
gradio	patch

• Maintainers can select this checkbox to manually select packages to update.

With the following changelog entry.

Fix data model for gr.DataFrame

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[hysts]

Thanks! LGTM!