Transform FlingRing when attracted instead of spawning new Ring

Fixes #1218 (closed).

When a Fling Ring gets attracted by an Attraction Shield, it spawns a new ring which increments the Perfect Bonus counter per ring spawned.

This commit has the Fling Ring instead turn itself into the type of its 'painchance' along with its flags and spawn state instead of spawning a new ring and deleting itself.