Removed memory leaks due to GUI_App::app_config, GUI_App::preset_bundle and GUI_App::preset_updater not being deleted

src/slic3r/GUI/GUI_App.cpp

@@ -141,6 +141,18 @@ GUI_App::GUI_App()
     , m_imgui(new ImGuiWrapper())
 {}
 
+GUI_App::~GUI_App()
+{
+    if (app_config != nullptr)
+        delete app_config;
+
+    if (preset_bundle != nullptr)
+        delete preset_bundle;
+
+    if (preset_updater != nullptr)
+        delete preset_updater;
+}
+
 bool GUI_App::OnInit()
 {
     try {

src/slic3r/GUI/GUI_App.hpp

@@ -95,6 +95,7 @@ public:
     bool            initialized() const { return m_initialized; }
 
     GUI_App();
+    ~GUI_App();
 
     static unsigned get_colour_approx_luma(const wxColour &colour);
     static bool     dark_mode();