let si-phonetic-dynamic survive libreoffice losing focus and regain it cycle
and still use surrounding text. It should be safe to report that we can provide
surrounding text but there isn't any during the time window when there is no
focus window, because the focus in event was received but it hasn't arrived yet
because that happens on a postuserevent.

Change-Id: I0481c42208953f2a0618aaed7b0d9e9f3e7bda07