Make the DPM account strings system-APIs.

Bug: 33670246
Test: After making the CTS change in the same topic:
 cts-tradefed run cts --skip-device-info --skip-preconditions --skip-system-status-check com.android.compatibility.common.tradefed.targetprep.NetworkConnectivityChecker -a armeabi-v7a -l INFO -m CtsDevicePolicyManagerTestCases -t com.android.cts.devicepolicy.AccountCheckHostSideTest

Change-Id: Icefb6aec04a5ec805313e027424e99bdbf769e67
diff --git a/core/java/android/app/admin/DevicePolicyManager.java b/core/java/android/app/admin/DevicePolicyManager.java
index f1ccabe..eda7f5f 100644
--- a/core/java/android/app/admin/DevicePolicyManager.java
+++ b/core/java/android/app/admin/DevicePolicyManager.java
@@ -1773,10 +1773,14 @@
      *     if any of the accounts have it.
      * </ul>
      */
+    @SystemApi
+    @TestApi
     public static final String ACCOUNT_FEATURE_DEVICE_OR_PROFILE_OWNER_ALLOWED =
             "android.account.DEVICE_OR_PROFILE_OWNER_ALLOWED";
 
     /** @hide See {@link #ACCOUNT_FEATURE_DEVICE_OR_PROFILE_OWNER_ALLOWED} */
+    @SystemApi
+    @TestApi
     public static final String ACCOUNT_FEATURE_DEVICE_OR_PROFILE_OWNER_DISALLOWED =
             "android.account.DEVICE_OR_PROFILE_OWNER_DISALLOWED";