[tabbox] prevent dangling popups when switching on Wayland

If some popups of active window present, there was glitches on switching
such as stale popups or the popup happened below window.
Dismissing all the popups solves the problem.

BUG: 431046

src/tabbox/tabbox.cpp

@@ -1017,6 +1017,10 @@ void TabBox::navigatingThroughWindows(bool forward, const QKeySequence &shortcut
         // CDE style raise / lower
         CDEWalkThroughWindows(forward);
     } else {
+        workspace()->forEachAbstractClient([](Toplevel *toplevel) {
+            if (toplevel->isPopupWindow())
+                toplevel->popupDone();
+        });
         if (areModKeysDepressed(shortcut)) {
             if (startKDEWalkThroughWindows(mode))
                 KDEWalkThroughWindows(forward);