[welcome] Don't enable next early

- Next was enabled early; presumably to cover the case that no requirements
   were checked and the requirements checker never emitted an update signal.
   Drop that since the module manager is now responsible for doing that checking.

src/modules/welcome/WelcomeViewStep.cpp

@@ -34,7 +34,6 @@ WelcomeViewStep::WelcomeViewStep( QObject* parent )
     , m_requirementsChecker( new GeneralRequirements( this ) )
 {
     connect( Calamares::ModuleManager::instance(), &Calamares::ModuleManager::requirementsComplete, this, &WelcomeViewStep::nextStatusChanged );
-    emit nextStatusChanged( true );
     m_widget = new WelcomePage();
 }