Set expected pin length in constructor.

In the bug, it seems clear that the pinlength field is set to 0. This
means that the start appar animation is not called here but the view is
inflated...Having the field at 0 is causing an ANR. I believe this is
likely because we are calling reset somewhere before we show the view.

Test: Open bouncer and authenticate auto confirmation pin bouncer.
Fixes: 281424496
Change-Id: I776645ea633e49e45e8e30386cfc91bff3339f72

packages/SystemUI/src/com/android/keyguard/KeyguardPinViewController.java

@@ -62,6 +62,7 @@ public class KeyguardPinViewController
         mLockPatternUtils = lockPatternUtils;
         mFeatureFlags = featureFlags;
         mBackspaceKey = view.findViewById(R.id.delete_button);
+        mPinLength = mLockPatternUtils.getPinLength(KeyguardUpdateMonitor.getCurrentUser());
     }
 
     @Override
@@ -99,7 +100,6 @@ public class KeyguardPinViewController
     @Override
     public void startAppearAnimation() {
         if (mFeatureFlags.isEnabled(Flags.AUTO_PIN_CONFIRMATION)) {
-            mPinLength = mLockPatternUtils.getPinLength(KeyguardUpdateMonitor.getCurrentUser());
             mPasswordEntry.setUsePinShapes(true);
             updateAutoConfirmationState();
         }