Add a "smart campaign" constraint to the "data value changes" trigger and "changed data value" filter

Currently, if we want to detect a changed data value that was done by a specific smart campaign, we have to use the "source" field which is a plain text field, together with a "contains" operator. This is error prone (if the Smart Campaign name changes, it stops working) and slow.

It would be better to have a "smart campaign" constraint, in which we would be able to specifically choose a smart campaign.

-Greg