API to disable undo/redo functionality

Similar to https://bugreports.qt.io/browse/QTBUG-83036

Feature request to add an API to disable undo/redo stack functionality completely. Could be useful for a password field or otherwise sensitive information.

Currently, the only way to prevent undo operation on a QML TextField is to catch Keys.onPressed events, and match them against StandardKey.Undo which is very hacky, error-prone, and likely to be work-aroundable by calling undo() method from C++ (even function undo() override in QML wouldn't help).

Inspired by this merge request: https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/1788