If you don’t learn anything in the interview, that’s bad. If you are bored in the interview, that’s really bad. A good interview should feel like a conversation, not questions and responses.
"Here is the stuff of originality. For it is in the totality of experience reckoned with, filed, and forgotten, that each man is truly different from all others in the world." - Ray Bradbury
To signal a desire for learning, do cool things that require you to learn and do more than the job requires. Employers are, in general, sort of like archeologists: They study artifacts to understand the people who made them. So make artifacts that demonstrate you like to learn things.