Closes all popup menus when loading map in editor

The targets of many popup menus become invalid when loading or creating a new map with the editor hotkeys, so all popup menus have to be closed in this case, otherwise this can cause crashes with several different popups.

src/game/editor/editor.cpp

@@ -6577,6 +6577,7 @@ void CEditor::RenderMousePointer()
 
 void CEditor::Reset(bool CreateDefault)
 {
+	UI()->ClosePopupMenus();
 	m_Map.Clean();
 
 	mem_zero(m_apSavedBrushes, sizeof m_apSavedBrushes);