The current code only updates the alignment if the width of the
TextEdit changed, but we must also check if the height has changed.

Task-number: QTBUG-36069

[ChangeLog][QtQuick][TextEdit] Fixed TextEdit not vertically aligning
its text after having its height changed.

Change-Id: I0b2d6a7384457ca1018fc9899c82699e8ecfcbd4
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>