the point of an internship being penultimate/final is that it funnels into a job the following year after you graduate. this is why companies run internships at all. paying a student to run around their office is very unprofitable otherwise.
now if you don't want that job at that company, you cap for the internship about your 'expected' graduation date (in the application and resume etc.), and if they question it because say your transcript has a different date, you cap it with an excuse like 'oh i'm planning to drop my second major and graduate in (insert when their program wants u to graduate)'. and then if they give you the internship and somehow give you a graduate offer, turn it down via some more cap without making it obvious that you capped in the first place. granted, you're probably not getting a job at that company again, and maybe there's some sort of shared blacklist between certain companies