Script macro doesn't load attached JARs when using the "jars" parameter

Follow this steps to reproduce:

• Create a new page with this code and save:

  {{groovy}}
  import com.stripe.Stripe;
  {{/groovy}}
  

• You should get an exception "unable to resolve class com.stripe.Stripe" as expected
• Download the JAR attached to this issue and attach it to your page
• Modify the page code to:

  {{groovy jars="attach:stripe-java-20.30.0.jar"}}
  import com.stripe.Stripe;
  {{/groovy}}
  

Expected: don't get any exception.
Actual: you still get the "unable to resolve class com.stripe.Stripe", which seems to indicate that the Groovy (Script) macro didn't manage to load the indicated JAR from the page attachments.