Even if the Field is not added to the Screen, the Field's Server-Side Behaviour is still able to work

Steps to reproduce

1. Update the Create Issue Screen for the project and remove the Description field as shown below:-
   
2. Create a Server-Side Behaviour for the Description field and add the code below:

   def summary = getFieldById("summary")
   summary.setFormValue("Testing Summary")
   

   Below is the print screen of the Behaviour configuration:-
   

3. Create an issue for the project

Current Behaviour

When the Create Issue screen appears, the Summary field's form value which was set in the Description field's Server-Side Behaviour are displayed.

Expected Behaviour

The Summary field's form value set in the Description field's Server-Side Behaviour should not be triggered unless the Description field is added to the screen.