Fix PHPStan L1 errors "Function Drupal\Core\Executable\ExecutableInterface::execute() invoked with 1 parameter, 0 required." in ActionBase

Spokje → closed merge request !5097

The current MR contains no BC-stuff whatsoever, because of two reasons:

1. I want to seek blessing for the current approach before wandering into BC-land.
2. I genuinely have no clue if and how to approach this.

Putting this to NR for 1 and guidance on 2.

Not sure who can give that blessing, can ping them though?

We can't add the void return here, because that breaks BC for existing actions. I'm also wary about removing the parent interface because if something is relying on ExecutableInterface then suddenly that will start failing.

Can we just add this to ActionInterface while keeping ExecutableInterface satisfied?

  public function execute($object = NULL);

Thanks @longwave for taking a look.