qquicktextinput: Fix validation for IM event

If validation did not pass after text pre-editing is finished, it need
to be roll back to state before pre-editing started.

Before this change, if validation did not pass, text was always rolled
back to previous state. In pre-editing text case, it means back to the
state in which part of the text was removed (and later changed to
pre-edited text). It may cause a situation of removing part of the text
that was already validated

Fixes: QTBUG-90239
Change-Id: I3ec39e0f6b8a93d4e6fd190af30d4c80a0e495eb
Reviewed-by: Rami Potinkara <rami.potinkara@qt.io>
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
(cherry picked from commit b1ae151acc80254ab0ec2937c55b99223205875c)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

0 files changed, 0 insertions, 0 deletions