Qt: window resize handle overlaps with interactive controls with CSD on Windows

There are multiple controls in the interface that are interactive, such as play queue scroll bar and the seek bar. Currently, resize handles are inside the window frame, this makes it impossible to interact with the controls placed near the window frame.

This has been a problem since the very beginning, but with !6177 (merged) it is more obvious now.

If Qt 6.9's Qt::ExpandedClientAreaHint preserves having resize handle outside the window frame as with SSD, that can be used.