Gui: Respect both content size and minimum width for buttons

This is a hacky fix for https://github.com/FreeCAD/FreeCAD/issues/23607

Basically after widget is shown or polished we enforce it's minimum size to at
least cover the minimum size hint - something that QSS ignores if min-width is
specified.

src/Gui/PreferencePages/DlgSettingsGeneral.cpp

@@ -275,10 +275,7 @@ void DlgSettingsGeneral::saveSettings()
     hGrp->SetBool("TiledBackground", ui->tiledBackground->isChecked());
 
     if (themeChanged) {
-        auto qtStyle = QString::fromStdString(hGrp->GetASCII("QtStyle"));
-
         saveThemes();
-        qApp->setStyle(qtStyle);
     }
 }