client: Drop assert in frame size syncing

Whilst this assert is true for a normal application workflow
such as QtQuick, it's not something we can guarantee with all
applications.

If the assert is not true, the absolutely worst case is the
same glitchy resizing that we had in 6.8 and older.

Fixes: QTBUG-134126
Pick-to: 6.9
Pick-to: 6.9.0
Change-Id: I43b660d771d628ceedce9407fd146b48074557f9
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

src/plugins/platforms/wayland/qwaylandwindow.cpp

@@ -697,7 +697,6 @@ void QWaylandWindow::applyConfigure()
     // This could be improved in future as we 're blocking for not just the frame to finish but one additional extra frame.
     if (mInFrameRender)
         QWindowSystemInterface::handleExposeEvent<QWindowSystemInterface::SynchronousDelivery>(window(), QRect(QPoint(0, 0), geometry().size()));
-    Q_ASSERT(!mInFrameRender);
     if (mShellSurface)
         mShellSurface->applyConfigure();