UMG Event Track events may not fire if they are too close to the end of the animation

Every tick, we evaluate the range of time that has passed to see if any events on the event track need to be fired. However, when we hit the end of a loop, we have to manually set our LastPosition back to the beginning as well to avoid sweeping the entire range of the animation looking for events to fire. This causes events that are extremely close to the end of the animation to be skipped.

1. Create a UMG widget with an animation
2. Add an event track and place a key at the end of the animation range
3. Bind the key to a blueprint event
4. Event won't fire