The file mactrack_actions.php will throw and error if an the $save array is discarded by another plugin

[TheWitness]

Describe the bug Cacti's api_plugin_hook_function() requires that an array be passed to all plugins leveraging the hook. When a plugin discards or does not return the array, then plugins downstream from the first plugin will throw errors. In the case of MacTrack, it assumes that the array is present and that there will be a drp_action as one of the array indexes. This is in fact not always true, and can lead to errors.

Expected behavior Ensure that MacTrack does not throw an error in these cases.