Add a "More" item for the new default apps list.

If Settings handles the new intent action, a "More" item will appear
in the new default apps list, and clicking it will launch that intent.

Bug: 124452117
Bug: 127745414
Test: build
Change-Id: I4bb08489b77de12fd20d85260edba9e58252712a
diff --git a/api/system-current.txt b/api/system-current.txt
index 48b1385..5e6e75e 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -6055,6 +6055,7 @@
     field public static final String ACTION_ENTERPRISE_PRIVACY_SETTINGS = "android.settings.ENTERPRISE_PRIVACY_SETTINGS";
     field public static final String ACTION_LOCATION_CONTROLLER_EXTRA_PACKAGE_SETTINGS = "android.settings.LOCATION_CONTROLLER_EXTRA_PACKAGE_SETTINGS";
     field public static final String ACTION_MANAGE_DOMAIN_URLS = "android.settings.MANAGE_DOMAIN_URLS";
+    field public static final String ACTION_MANAGE_MORE_DEFAULT_APPS_SETTINGS = "android.settings.MANAGE_MORE_DEFAULT_APPS_SETTINGS";
     field public static final String ACTION_NOTIFICATION_POLICY_ACCESS_DETAIL_SETTINGS = "android.settings.NOTIFICATION_POLICY_ACCESS_DETAIL_SETTINGS";
     field public static final String ACTION_REQUEST_ENABLE_CONTENT_CAPTURE = "android.settings.REQUEST_ENABLE_CONTENT_CAPTURE";
     field public static final String ACTION_SHOW_ADMIN_SUPPORT_DETAILS = "android.settings.SHOW_ADMIN_SUPPORT_DETAILS";
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 1cab250..d0d6ceb 100644
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -1501,6 +1501,22 @@
             = "android.settings.MANAGE_DEFAULT_APPS_SETTINGS";
 
     /**
+     * Activity Action: Show More default apps settings.
+     * <p>
+     * In some cases, a matching Activity may not exist, so ensure you safeguard against this.
+     * <p>
+     * Input: Nothing.
+     * <p>
+     * Output: Nothing.
+     *
+     * @hide
+     */
+    @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
+    @SystemApi
+    public static final String ACTION_MANAGE_MORE_DEFAULT_APPS_SETTINGS =
+            "android.settings.MANAGE_MORE_DEFAULT_APPS_SETTINGS";
+
+    /**
      * Activity Action: Show notification settings.
      *
      * @hide