Stop using cameraProtectionAnimator field

Previously, we were canceling cameraProtectionAnimator and rimAnimator separately when the latter was an AnimatorSet that includes cameraProtectionAnimator as well. The hypothesis is that cameraProtectionAnimator becomes null because we run `rimAnimator?.cancel() -> cameraProtectionAnimator#onAnimationEnd` and then we create a new rim animator with the null cameraProtectionAnimator

Bug: 392032258
Flag: com.android.systemui.face_scanning_animation_npe_fix
Test: verified scanning animation works as expected
Change-Id: I48199e7caedbdb13cf23c877e3c71eb1c191686e