feat(sdk): add logout helper and SDK method

[AurimarL]

What?

This PR introduces a new logout helper and corresponding SDK method for authentication collections.
It mirrors the existing login helper, allowing developers to easily call the Payload logout endpoint with proper typing.

Why?

Currently, the SDK provides a typed login method but lacks a counterpart for logging out.
By adding this method, SDK users can:

• Log out from the current session
• Optionally log out from all sessions (allSessions=true)
• Rely on fully typed options and results, improving DX

How?

• Added LogoutOptions and LogoutResult types
• Implemented logout helper function using sdk.request
• Extended the SDK class with logout method, mirroring the login method’s pattern

Example usage

const result = await sdk.logout({
  collection: 'users',
  allSessions: false,
})

console.log(result.message)
// -> "You have been logged out"

[r1tsuu]

Thanks!
Needs an integration test, there is one already for login

payload/test/sdk/int.spec.ts

Lines 235 to 242 in 4b193da

	it('should execute login', async () => {
	const res = await sdk.login({
	collection: 'users',
	data: { email: testUserCredentials.email, password: testUserCredentials.password },
	})
	expect(res.user.email).toBe(testUserCredentials.email)
	})

Your test would verify that the session was deleted.

[r1tsuu]

Use the args property of sdk.request instead like in all other operations.

[AurimarL]

this one is like verifyEmail, no args is used

[r1tsuu]

Looks like the new test is failing.