xcb: Avoid recreating xcb window in QXcbWindow::requestActivateWindow()
12203e94 exposes the issue in xcb qpa plugin.
We should not recreate xcb window via the call of focusWindow->winId().
Fixes: QTBUG-123032 Pick-to: 6.7 6.6 6.5 6.2 5.15 Change-Id: I6da4f3e64a9d7a92a2aab714591986c5d128fbd4 Reviewed-by: Tor Arne Vestbø tor.arne.vestbo@qt.io (cherry picked from commit 23a90633)