Update udfps icon alpha after bouncer vis changes

Also make sure mInputBouncerHiddenAmount is set correctly when the
bouncer isn't being dragged.

Test: manual
Fixes: 190415776
Change-Id: I4fce36fc17baf7218c6a7aff2f45b8790b971aca

packages/SystemUI/src/com/android/systemui/biometrics/UdfpsKeyguardViewController.java

@@ -358,7 +358,10 @@ public class UdfpsKeyguardViewController extends UdfpsAnimationViewController<Ud
                     mIsBouncerVisible = mKeyguardViewManager.bouncerIsOrWillBeShowing();
                     if (!mIsBouncerVisible) {
                         mInputBouncerHiddenAmount = 1f;
+                    } else if (mKeyguardViewManager.isBouncerShowing()) {
+                        mInputBouncerHiddenAmount = 0f;
                     }
+                    updateAlpha();
                     updatePauseAuth();
                 }