root: recreate the qml engine on reload instead of clearing it

This causes singletons to be recreated instead of kept alive.

src/wayland/wlr_layershell/window.hpp

@@ -26,7 +26,7 @@ enum Enum {
 };
 Q_ENUM_NS(Enum);
 
-} // namespace Layer
+} // namespace WlrLayer
 
 ///! WlrLayershell keyboard focus mode
 namespace WlrKeyboardFocus { // NOLINT
@@ -47,7 +47,7 @@ enum Enum {
 };
 Q_ENUM_NS(Enum);
 
-} // namespace KeyboardFocus
+} // namespace WlrKeyboardFocus
 
 class QSWaylandLayerSurface;