pcbnew_action_plug tracks items that were modified within a plugin. In the case of
deletion, the old object is no longer valid. This commit turns off the call to delete
if a plugin is active.
This plugin mechanism is enabled only if option -DKICAD_SCRIPTING_ACTION_MENU=ON (it is off by default)
It imply -DKICAD_SCRIPTING=0N
This is currently for testing purposes only for developers, not yet for users.