Fix event triggers and recent regressions related to gr.DataFrame

[abidlabs]

Fixes a few things that were broken or broke as a result of recent PRs

• Does not fire .change() and .input() events when the page first loads (closes: The .input() and .change() events in gr.Dataframe are also triggered at function updates and at app start #8231 and adds a test)
• Fixes .input() event to fire when a user inputs data (because of a recent regression, it was not firing at all)
• Fixes the cell selection logic so that a header and cell cannot be selected at the same time (recent regression)

Some other minor refactoring of Table.svelte (more to come in a separate PR)

[gradio-pr-bot]

🪼 branch checks and previews

•	Name	Status	URL
	Spaces	ready!	Spaces preview
	Website	building...
	Storybook	ready!	Storybook preview
🦄	Changes	detected!	Details

---

Install Gradio from this PR

pip install https://gradio-pypi-previews.s3.amazonaws.com/215b9e933f9804ac80da3631da16d1c221172271/gradio-5.12.0-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@215b9e933f9804ac80da3631da16d1c221172271#subdirectory=client/python"

Install Gradio JS Client from this PR

npm install https://gradio-npm-previews.s3.amazonaws.com/215b9e933f9804ac80da3631da16d1c221172271/gradio-client-1.10.0.tgz

Use Lite from this PR

<script type="module" src="https://gradio-lite-previews.s3.amazonaws.com/215b9e933f9804ac80da3631da16d1c221172271/dist/lite.js""></script>

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/dataframe	patch
gradio	patch

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

With the following changelog entry.

Fix event triggers and recent regressions related to gr.DataFrame

Maintainers or the PR author can modify the PR title to modify this entry.

Something isn't right?

• Maintainers can change the version label to modify the version bump.
• If the bot has failed to detect any changes, or if this pull request needs to update multiple packages to different versions or requires a more comprehensive changelog entry, maintainers can update the changelog file directly.

[aliabid94]

why arent these

	let previous_data_string = JSON.stringify(
			data.map((row) => row.map((cell) => String(cell.value)));
	let previous_headers_string = JSON.stringify(...)

Won't this cause a change dispatch immediately because of the

 if (
			current_data_string !== previous_data_string ||
			current_headers_string !== previous_headers_string
		)

later

[abidlabs]

It doesn't dispatch immediately, but I'm not sure why. I can make the change though

[abidlabs]

Fixed

[aliabid94]

initial dispatches often don't, but I think it's flaky. Better to remove

[aliabid94]

tested, lgtm!

[abidlabs]

Thanks @aliabid94! Fixed the issue above, will merge in once CI passes