Qt Designer: Change the default mode to docked for macOS, too

[ChangeLog][Qt Designer] Qt Designer now starts in docked mode
by default on macOS, too.

Pick-to: 6.8
Fixes: QTBUG-127780
Change-Id: I397501069bd4bd84c5b76d5b393253aff9b0bf56
Reviewed-by: Jarek Kobus <[email protected]>
Reviewed-by: Tor Arne Vestbø <[email protected]>

Author: FriedemannKleint

src/designer/src/designer/qdesigner_settings.cpp

@@ -180,11 +180,7 @@ void QDesignerSettings::setUiMode(UIMode mode)
 
 UIMode QDesignerSettings::uiMode() const
 {
-#ifdef Q_OS_MACOS
-    const UIMode defaultMode = TopLevelMode;
-#else
-    const UIMode defaultMode = DockedMode;
-#endif
+    constexpr UIMode defaultMode = DockedMode;
     UIMode uiMode = static_cast<UIMode>(value(u"UI/currentMode"_s, defaultMode).toInt());
     return uiMode;
 }