Add eventsource polyfill for Node.js and browser environments

[hannahblair]

Description

Replaces the Web API eventsource with eventsource to support Node.js environments. Also addresses window is not defined errors in Node.js.

To test, run the following in a node environment:

import { Client } from "@gradio/client";

const test = async () => {
    try {
	const app = await Client.connect("gradio/hello_world");
	const result = await app.predict("/predict", ["John"]);
	console.log("Result:", result);
    } catch (error) {
	console.error("Error:", error);
    }
};

(async () => {
	await test();
})();

Closes: #6352
Closes: #7103

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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]

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---

Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/d3c2e57646ef2bf9576c34cb7ed232ced11c00cf/gradio-4.28.3-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@d3c2e57646ef2bf9576c34cb7ed232ced11c00cf#subdirectory=client/python"

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
@gradio/client	patch
@gradio/upload	patch
gradio	patch

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

With the following changelog entry.

Add eventsource polyfill for Node.js and browser environments

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[pngwn]

I think it would be good to run these test in node as well. We can doo this by creating a new script:

"pnpm:test:client:node": "vitest client/js -c path/to/config --mode=test_node"

Then in the vite.config.ts check the mode is test_node and set the test.environment to "node". We would also need to check anything that is currently checking for just mode == "test" and also catch the new node-test.

[hannahblair]

@pngwn good thinking! i've added that now

i'm not sure if there's anything relevant that's checking for mode == "test" 🤔

[pngwn]

Small comment but looks great. Thanks for sorting this one out @hannahblair! This will be a huge boost to quality!

[pngwn]

Also closes #5840

I mean it closes this: ##5583

[pngwn]

Looks great! Thanks for ironing out the kinks with this one @hannahblair! And sorry for the back and forth!