Minor changes in Section 8.3.3

Better readability:

• from "...performed by (a collaboration of) two or more business actors, business roles, or business collaborations." to "performed by (a collaboration of) two or more business internal active structure elements."
• from "A business interaction may be triggered by, or trigger, any other business behavior element (business event, business process, business function, or business interaction)." to "A business interaction may be triggered by, or trigger, any other internal business behavior element or a business event."
• from "A business collaboration or two or more business actors or roles may be assigned to a business interaction." to "A business collaboration or two or more business internal active structure elements.may be assigned to a business interaction."