wayland/xdg-shell: Dismiss instead of destroy invalid popup

Destroying is insufficient as it doesn't end any popup pointer grab, if
the dismissed popup was the last. This would later hit an assert as the
popup grab is assumed to always have at least one popup in its chain.

Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/2728
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2940>

(cherry picked from commit 50a37a7f)

src/wayland/meta-wayland-xdg-shell.c

@@ -1155,7 +1155,7 @@ dismiss_invalid_popup (MetaWaylandXdgPopup *xdg_popup)
           top_xdg_popup = meta_wayland_xdg_popup_from_surface (top_popup_surface);
 
           xdg_popup_send_popup_done (top_xdg_popup->resource);
-          meta_wayland_popup_destroy (top_xdg_popup->popup);
+          meta_wayland_popup_dismiss (top_xdg_popup->popup);
 
           if (top_xdg_popup == xdg_popup)
             break;