[Live] add TestLiveComponent::actingAs()

[kbond]

Q	A
Bug fix?	no
New feature?	yes
Tickets	(slack discussion)
License	MIT

$this->createLiveComponent('my_component')
    ->actingAs($user) // UserInterface
    ->...
;

Additionally, the test client can be passed to InteractsWithLiveComponents::createLiveComponent():

// customize the test client
$client = self::getContainer()->get('test.client');

// do some stuff with the client (ie login user via form)

$testComponent = $this->createLiveComponent(
    name: 'MyComponent',
    data: ['foo' => 'bar'],
    client: $client,
);

[weaverryan]

Awesomesauce