Add predictive back aconfig flag

Bug: 309545085
Flag: ACONFIG com.android.window.flags.predictive_back_system_animations DISABLED
Test: atest BackAnimationPreferenceControllerTest; Manual, i.e. building and verifying correct behaviour for different flag configurations
Change-Id: I3f478dc23bbfeb1f13cae64f3d04b3210841731d

src/com/android/settings/development/BackAnimationPreferenceController.java

@@ -16,6 +16,8 @@
 
 package com.android.settings.development;
 
+import static com.android.window.flags.Flags.predictiveBackSystemAnimations;
+
 import android.content.Context;
 import android.provider.Settings;
 
@@ -55,6 +57,11 @@ public class BackAnimationPreferenceController extends DeveloperOptionsPreferenc
         mFragment = fragment;
     }
 
+    @Override
+    public boolean isAvailable() {
+        return !predictiveBackSystemAnimations();
+    }
+
     @Override
     public String getPreferenceKey() {
         return BACK_NAVIGATION_ANIMATION_KEY;