[TRIGGER] Slack New Saved Message

[luancazarine]

Describe the event source. What app is this for, and what event does the trigger correspond to? Triggers when you save a message.

Please provide a link to the relevant API docs for the specific service / operation this trigger is tied to. https://api.slack.com/events/star_added

In https://github.com/PipedreamHQ/pipedream/issues/3299. was asked to create a Source that triggers just when you save a message. I created a new source with this behavior named 'New Star Added Message', but talking with @dannyroosevelt it was decided that is better delete this one and just add a filter with a string[] prop in the 'New Start Added' Source