Enable Copy Embedded File Reference context menu on macOS

Using wxID_COPY checks under the hood whether the item
should be enabled or not; we need to use a custom ID
to avoid this behavior.

common/dialogs/panel_embedded_files.cpp

@@ -84,9 +84,11 @@ void PANEL_EMBEDDED_FILES::resizeGrid()
 void PANEL_EMBEDDED_FILES::onGridRightClick( wxGridEvent& event )
 {
     wxMenu menu;
-    menu.Append( wxID_COPY, _( "Copy Embedded Reference" ) );
+    const wxWindowID id = NewControlId();
+    menu.Append( id, _( "Copy Embedded Reference" ) );
 
-    menu.Bind( wxEVT_COMMAND_MENU_SELECTED,
+    menu.Bind(
+            wxEVT_COMMAND_MENU_SELECTED,
             [&]( wxCommandEvent& )
             {
                 int row = event.GetRow();
@@ -100,7 +102,8 @@ void PANEL_EMBEDDED_FILES::onGridRightClick( wxGridEvent& event )
                         wxTheClipboard->Close();
                     }
                 }
-        }, wxID_COPY );
+            },
+            id );
 
     PopupMenu( &menu );
 }