QWidgetTextControl: ignore invalid input method event
requested to merge asturmlechner/qtbase:asturmlechner/QTBUG-112953-QWidgetTextControl-ignore-invalid-im-event into kde/5.15
to avoid update the text document.
Fixes: QTBUG-112953 Pick-to: 6.5 6.2 5.15 Change-Id: Ib72de57133314e4eb38a15758b8318d901196d75 Reviewed-by: Axel Spoerl axel.spoerl@qt.io Reviewed-by: Artem Sokolovskii artem.sokolovskii@qt.io (cherry picked from commit 70f064f2)