Fix crash when quitting sdrangel when the SID window is open

Fixes a stack exhaustion that happens in some machines/compiler combinations.
Fixes #2119

plugins/feature/sid/sidgui.cpp

@@ -292,7 +292,11 @@ SIDGUI::~SIDGUI()
     clearFromMap();
 
     delete m_goesXRay;
-    delete m_solarDynamicsObservatory;
+    if (m_solarDynamicsObservatory)
+    {
+        delete m_player;
+        delete m_solarDynamicsObservatory;
+    }
     delete ui;
 }