CE_ComboBoxLabel painting not called anymore on QProxyStyle, due to QStyleSheetStyle

The CE_ComboBoxLabel painting of the base style or any QProxyStyle sitting on top of it, is not called anymore, due to the recent removal of the check for any valid CSS rules at the beginning of the CE_ComboBoxLabel painting in the QStyleSheetStyle.
This results in the CSS style always doing the painting, even when no CSS is applied to the combobox at all.
In the past the check   if (!rule.hasBox()) ensured that at the end of the function baseStyle()->drawControl() was called, now we never get to it.

This is a regression that got introduced by the fix for: QTBUG-131761 - Incorrect display of :selected state of QCombobox on "windows" style plugin
https://codereview.qt-project.org/c/qt/qtbase/+/609484/2/src/widgets/styles/qstylesheetstyle.cpp

Removed CSS check:

case CE_ComboBoxLabel:        
    if (!rule.hasBox()) // <- check for CSS has been removed, QStyleSheetStyle now always paints
        break;