Force basic render loop on Wayland
In Qt 5, qtwayland can't ensure that the wl_surface lives as long as qtquick render thread needs it. If the wl_surface is destroyed while it's still being used, it will eventually lead to a crash.
It's fixed in Qt 6 using RHI abstractions. We tried to add equivalent QWaylandWindow::beginFrame() and QWaylandWindow::endFrame() functions, but that didn't work well. QOpenGLContext::makeCurrent() and QOpenGLContext::swapBuffers() don't cut for the task.
As a shortterm solution, this patch makes plasma-integration's qtquick settings module to force basic render loop on wayland. Threaded render loop is still used on X11.