Auto hide IllustrationPreference when lottie file is empty

Flag: com.android.settingslib.widget.flags.auto_hide_lottie_res
Bug: 337873972
Test: unit test
Test: manual: delete `lottie_adaptive_brightness.json` from overlay, navigate to Display > Adaptive Brightness -- verify no empty container
Change-Id: I873976d3e87b119a3ee690d95c68149f249fe7a9
diff --git a/packages/SettingsLib/IllustrationPreference/Android.bp b/packages/SettingsLib/IllustrationPreference/Android.bp
index 6407810..c3a91a2 100644
--- a/packages/SettingsLib/IllustrationPreference/Android.bp
+++ b/packages/SettingsLib/IllustrationPreference/Android.bp
@@ -21,6 +21,7 @@
         "SettingsLibColor",
         "androidx.preference_preference",
         "lottie",
+        "settingslib_illustrationpreference_flags_lib",
     ],
 
     sdk_version: "system_current",
@@ -31,3 +32,24 @@
         "com.android.permission",
     ],
 }
+
+aconfig_declarations {
+    name: "settingslib_illustrationpreference_flags",
+    package: "com.android.settingslib.widget.flags",
+    container: "system",
+    srcs: [
+        "aconfig/illustrationpreference.aconfig",
+    ],
+}
+
+java_aconfig_library {
+    name: "settingslib_illustrationpreference_flags_lib",
+    aconfig_declarations: "settingslib_illustrationpreference_flags",
+
+    min_sdk_version: "30",
+
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.permission",
+    ],
+}