Ensure @gradio/client's submit iterator releases as expected

[pngwn]

Description

We weren't existing the iterator when the prediction completed.

Build the client and put the following file in client/js and run it with node test.js:

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

async function run() {
	const client = await Client.connect(
		"gradio/test_chatinterface_streaming_echo_main",
		{
			events: ["data", "status"]
		}
	);
	const result = client.submit("/chat", {
		message: "Hello!!"
	});

	for await (const msg of result) {
		console.log(msg);
	}

	console.log("ALL DONE");
}

run();

Closes #8502.

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Tests

1. PRs will only be merged if tests pass on CI. To run the tests locally, please set up your Gradio environment locally and run the tests: bash scripts/run_all_tests.sh

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[gradio-pr-bot]

🪼 branch checks and previews

•	Name	Status	URL
	Spaces	ready!	Spaces preview
	Website	ready!	Website preview
🦄	Changes	detecting...

---

Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/9217688b8745636f0954b1da707edf0fa1fb157b/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@9217688b8745636f0954b1da707edf0fa1fb157b#subdirectory=client/python"

Install Gradio JS Client from this PR

npm install https://gradio-builds.s3.amazonaws.com/9217688b8745636f0954b1da707edf0fa1fb157b/gradio-client-1.2.1.tgz

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/client	patch
gradio	patch

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Ensure @gradio/client's submit iterator releases as expected

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