Only set `mEnded` to true if `pulseAnimationFrame` returns true

Previously this can set the value to false if `pulseAnimationFrame` returns false but the animation has already called its end listener and ended the animation, this would result in the value of `mEnded` being overwritten from true back to false and the `AnimatorSet` running indefinitely.

This can happen with an `ObjectAnimator` that is referencing a target that has been garbage collected, in this case `ObjectAnimator` will immediately cancel itself when animating values, which happens as part of `pulseAnimationFrame`, however the return value from `pulseAnimationFrame` is based only on the duration of the animation so even though the `ObjectAnimator` has ended by cancelling itself `pulseAnimationFrame` will return false as the current time has not exceeded the play time of the animator.

Change-Id: I08c7790346b092ad3cd8938bbe02973148ac108e