[8.x] Add a Passport Client factory to Passport publishing

[Orrison]

In the help documentation for 6.x and up there is reference in the testing section to test Client access with the method Passport::actingAsClient and that it takes a Client model created by a factory to be passed in. https://laravel.com/docs/6.x/passport#testing

use Laravel\Passport\Client;
use Laravel\Passport\Passport;

public function testGetOrders()
{
    Passport::actingAsClient(
        factory(Client::class)->create(),
        ['check-status']
    );

    $response = $this->get('/api/orders');

    $response->assertStatus(200);
}

Just trying that code out of the box fails since there is no published asset for a Laravel\Passport\Client factory. The user is left to make one on their own.
This will publish a Client factory that the user can use for this.

I don't believe it will break any existing features as it is just publishing a factory for the user. It could possibly overwrite one the user has already created if it was the same filename?
I think it will make testing this feature easier for Laravel users as they don't have to reference the oauth_clients table and create the factory themselves.

I don't have any tests included as I am not sure how to test the publish functionality and it seems the other publishes are not tested. If you would like me to write some tests please let me know. I could try harder to find a way to test that.

Thank you!

[driesvints]

If you bump the minimum Laravel components versions to v6.12.0 we can use the new loadFactoriesFrom method. But then they can't be adjusted so it's probably best to do a combination of both.

laravel/framework#31133