c6dd32da697e5a8052cbabe8c7605d27c43a8dfb qt: Replace obsolete functions of QDesktopWidget (Hennadii Stepanov)
1260ecd812e35185898fd555ad3e01d019072bcf qt: Add TextWidth() wrapper (Hennadii Stepanov)
Pull request description:
The following functions are obsolete in Qt 5.13:
- [QFontMetrics::width()](https://doc.qt.io/qt-5/qfontmetrics-obsolete.html#width)
- [QDesktopWidget::availableGeometry()](https://doc.qt.io/qt-5/qdesktopwidget-obsolete.html#availableGeometry)
- [QDesktopWidget::screenGeometry()](https://doc.qt.io/qt-5/qdesktopwidget-obsolete.html#screenGeometry)
This PR replaces them and does not change behavior.
This is a backport from Core PR16701