Hide tooltip window immediately before opening context menu

Tooltip internally uses TooltipDialog (a QWindow subclass) which runs a timer before it hides itself. This is done so it can be reused and to prevent flickering when switching between Tooltips quickly. However here it causes an issue, when closing a popup on Wayland, Qt closes all popups that were opened after it. This means when openening a ContextMenu while a Tooltip is shown, the TooltipDialog will hide itself after the window of the context menu has been created and close it in the process. As a workaround we can hide the window manually before creating the context menu. BUG: 417939 FIXED-IN:5.22