feat: add off method to ViteHotContext (issue #14185)

[vincer2040]

Description

This pr adds the ability to remove listeners added using import.meta.hot.on() as
requested in issue #14185

fix #14185

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the PR Title Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[bluwy]

The implementation looks great. Can we add a test for it around

vite/playground/hmr/hmr.ts

Lines 107 to 115 in 56c5f4f

	import.meta.hot.on('custom:foo', ({ msg }) => {
	text('.custom', msg)
	})
	// send custom event to server to calculate 1 + 2
	import.meta.hot.send('custom:remote-add', { a: 1, b: 2 })
	import.meta.hot.on('custom:remote-add-result', ({ result }) => {
	text('.custom-communication', result)
	})

and

vite/playground/hmr/__tests__/hmr.spec.ts

Lines 174 to 183 in 56c5f4f

	test('plugin hmr handler + custom event', async () => {
	const el = await page.$('.custom')
	editFile('customFile.js', (code) => code.replace('custom', 'edited'))
	await untilUpdated(() => el.textContent(), 'edited')
	})
	test('plugin client-server communication', async () => {
	const el = await page.$('.custom-communication')
	await untilUpdated(() => el.textContent(), '3')
	})

(new test cases, but those are existing examples)

[bluwy]

Looks great!

[sapphi-red]

Would you add off to the document?

vite/docs/guide/api-hmr.md

Lines 35 to 39 in 6868480

	// `InferCustomEventPayload` provides types for built-in Vite events
	on<T extends string>(
	event: T,
	cb: (payload: InferCustomEventPayload<T>) => void,
	): void

vite/docs/guide/api-hmr.md

Lines 167 to 183 in 6868480

	## `hot.on(event, cb)`
	Listen to an HMR event.
	The following HMR events are dispatched by Vite automatically:
	- `'vite:beforeUpdate'` when an update is about to be applied (e.g. a module will be replaced)
	- `'vite:afterUpdate'` when an update has just been applied (e.g. a module has been replaced)
	- `'vite:beforeFullReload'` when a full reload is about to occur
	- `'vite:beforePrune'` when modules that are no longer needed are about to be pruned
	- `'vite:invalidate'` when a module is invalidated with `import.meta.hot.invalidate()`
	- `'vite:error'` when an error occurs (e.g. syntax error)
	- `'vite:ws:disconnect'` when the WebSocket connection is lost
	- `'vite:ws:connect'` when the WebSocket connection is (re-)established
	Custom HMR events can also be sent from plugins. See [handleHotUpdate](./api-plugin#handlehotupdate) for more details.

[sapphi-red]

Thanks!