remove clearing cache

--this code was suspicious for crashes

app/dockview.cpp

@@ -1041,16 +1041,6 @@ bool DockView::event(QEvent *e)
 {
     emit eventTriggered(e);
 
-    if (e->type() == QEvent::Leave) {
-        engine()->collectGarbage();
-        engine()->trimComponentCache();
-        //! Important! this code creates a crash when there are two docks
-        //! running and the user clicks the Quit button, it is also
-        //! suspicious for some rare cases when removing a dock and the
-        //! dock is deleted after the 1min time limit of plasma
-        //!     engine()->clearComponentCache();
-    }
-
     return ContainmentView::event(e);
 }