Mobs target players after going to spectator from survival.

If you spawn a mob, and then go to /gamemode 0 and let it target you and then go to spectator mode (/gamemode 3) they will still target. It stops for creative mode.

Steps to Reproduce:
1. Spawn a mob
2. Go to gamemode 0 and let it target
3. Go to gamemode 3 and it will still target.