fix execute()" must be of the type int, "null" ret

[vdloo]

Broke somewhere after a Shopware 6 update:

shopware$ bin/console hypernode:skipwizard
13:54:35 CRITICAL  [console] Error thrown while running command "hypernode:skipwizard". Message: "Return value of "Hypernode\HypernodeShopware6Helpers\Command\SkipWizard::execute()" must be of the type int, "null" returned." ["exception" => TypeError { …},"command" => "hypernode:skipwizard","message" => "Return value of "Hypernode\HypernodeShopware6Helpers\Command\SkipWizard::execute()" must be of the type int, "null" returned."]

In Command.php line 259:

  Return value of "Hypernode\HypernodeShopware6Helpers\Command\SkipWizard::execute()" must be of the type int, "null" returned.

hypernode:skipwizard

For context see: symfony/symfony#33747