Am I wrong for reporting my closest childhood friend for academic misconduct after finding out she intentionally framed an innocent classmate for cheating just to secure the only available research position in our department?

We were competing for a single residency spot. My friend planted a cheat sheet in another aplicant's bag right before the final exam. That applicant got disqualified immediately, and my friend got the position. I found out because she accidentally left her notes containing the drafted cheat sheet at my apartment. When I confronted her, she admitted it but begged me to keep it a secret. She said this was her only chance to succeed. I couldn't live with the guilt, so I anonimously submitted the evidence to the dean. They investigated, cleared the other student, and expelled my friend permanently. Now her life is ruined, and mutual friends say I should have stayed loyal to her instead of helping a stranger.