As we are rolling out the user profile feature, we'd like to expand the [Usage API](https://www.elastic.co/guide/en/elasticsearch/reference/current/usage-api.html) to report usage stats of user profiles such as (1) number of enabled user profiles and (2) number of user profiles that are [activated](https://www.elastic.co/guide/en/elasticsearch/reference/current/security-api-activate-user-profile.html) over the past X days. 

Response of the Usage API already contains a `security` field that groups relevant stats from security related features. We expect the new stats for user profiles should be added under it as well, for example:
```
{
  "security: {
    "user_profile": {
      "activated": 78,
      "recently_activated": 42  <1>
    }
  }
}
```
<1> The use of `recently_` is chosen to avoid the field to be tied to a specific time period so it is easier to evolve the definition in future.

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/profile/ProfileServiceTests.java
import static java.util.Collections.emptyMap;
import static org.elasticsearch.common.util.concurrent.ThreadContext.ACTION_ORIGIN_TRANSIENT_NAME;
import static org.elasticsearch.test.ActionListenerUtils.anyActionListener;
import static org.elasticsearch.xpack.core.ClientHelper.SECURITY_ORIGIN;
import static org.elasticsearch.xpack.core.ClientHelper.SECURITY_PROFILE_ORIGIN;
import static org.elasticsearch.xpack.core.security.support.Validation.VALID_NAME_CHARS;
import static org.elasticsearch.xpack.security.Security.SECURITY_CRYPTO_THREAD_POOL_NAME;
import static org.elasticsearch.xpack.security.support.SecuritySystemIndices.SECURITY_PROFILE_ALIAS;
import static org.hamcrest.Matchers.anEmptyMap;
import static org.hamcrest.Matchers.arrayContaining;
import static org.hamcrest.Matchers.arrayWithSize;
import static org.hamcrest.Matchers.containsString;
import static org.hamcrest.Matchers.empty;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.hasItem;
import static org.hamcrest.Matchers.instanceOf;
import static org.hamcrest.Matchers.is;
import static org.hamcrest.Matchers.not;
import static org.hamcrest.Matchers.sameInstance;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
public class ProfileServiceTests extends ESTestCase {