ensure @gradio/client always returns the correct data

[pngwn]

Description

Closes #8508.

In handle_payload which we use to remove state data which is always null, we handle both inputs (request payload) and outputs (response payload) but we were treating everything as if they were inputs. So if there were no input components but there was data returned, it would be removed.

Can reproduce fix this script:

import { Client, handle_file } from "./dist/index.js";

async function generate(image_url) {
	const client = await Client.connect("TencentARC/InstantMesh", {
		events: ["status", "data"]
	});

	const image = await fetch(image_url);
	const image_blob = await image.blob();

	// This is working fine
	const result_mvs_image = await client.predict("/generate_mvs", [
		handle_file(image_blob),
		50,
		10000
	]);

	console.log(result_mvs_image);

	// This is returning empty data object
	const job = client.submit("/make3d", []);

	for await (const message of job) {
		if (message.type === "data") {
			console.log(message);
		}
	}
}

generate(
	"https://github.com/raw/gradio-app/gradio/main/test/test_files/bus.png"
);

Add it to client/js as test.js, run pnpm build and run node test.js.

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---

Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/da4ec7343dbf848047ec3f31d011242fa49727a6/gradio-4.37.2-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@da4ec7343dbf848047ec3f31d011242fa49727a6#subdirectory=client/python"

Install Gradio JS Client from this PR

npm install https://gradio-builds.s3.amazonaws.com/da4ec7343dbf848047ec3f31d011242fa49727a6/gradio-client-1.2.1.tgz

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🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/client	patch
gradio	patch

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With the following changelog entry.

ensure @gradio/client always returns the correct data

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[pngwn]

We just need to check which dependencies we care about here and set it accordingly, when handling inputs we use dependency.inputs when handling outputs we use dependency.outputs.

[pngwn]

I was getting an error about File not being defined. This check fixes it.

[hannahblair]

Ah dang, that's a bad bug. Thanks for fixing that @pngwn! Tested and works as expected.