overview: Do not trigger the toggle action twice

It's already connected as it's created by EffectTogglableState.

BUG: 470603

src/plugins/overview/overvieweffect.cpp

@@ -43,7 +43,6 @@ OverviewEffect::OverviewEffect()
 
     const QKeySequence defaultToggleShortcut = Qt::META | Qt::Key_W;
     auto toggleAction = m_state->toggleAction();
-    connect(toggleAction, &QAction::triggered, m_state, &EffectTogglableState::toggle);
     toggleAction->setObjectName(QStringLiteral("Overview"));
     toggleAction->setText(i18n("Toggle Overview"));
     KGlobalAccel::self()->setDefaultShortcut(toggleAction, {defaultToggleShortcut});