Update campaign_builder.md
Update campaign_builder.md

## Goal of that documentation update
Explain the different behavior of the app about the waiting time of attached actions for `Decisions` and `Conditions`.
haamop/documentation,npracht/documentation,npracht/documentation,mautic/documentation,mautic/documentation,escopecz/documentation,haamop/documentation,megumiteam/documentation,megumiteam/documentation,escopecz/documentation