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/main/java/org/elasticsearch/xpack/security/SecurityUsageTransportAction.java
final CountDown countDown = new CountDown(3);
        final Runnable doCountDown = () -> {
            if (countDown.countDown()) {
                var usage = new SecurityFeatureSetUsage(
                    enabled,
                    realmsUsageRef.get(),
                    rolesUsageRef.get(),
                    roleMappingUsageRef.get(),
                    sslUsage,
                    auditUsage,
                    ipFilterUsage,
                    anonymousUsage,
                    tokenServiceUsage,
                    apiKeyServiceUsage,
                    fips140Usage,
                    operatorPrivilegesUsage,
                    domainsUsageRef.get()
                );
                listener.onResponse(new XPackUsageFeatureResponse(usage));
            }
        };
        final ActionListener<Map<String, Object>> rolesStoreUsageListener = ActionListener.wrap(rolesStoreUsage -> {
            rolesUsageRef.set(rolesStoreUsage);
            doCountDown.run();
        }, listener::onFailure);
        final ActionListener<Map<String, Object>> roleMappingStoreUsageListener = ActionListener.wrap(nativeRoleMappingStoreUsage -> {
            Map<String, Object> usage = singletonMap("native", nativeRoleMappingStoreUsage);
            roleMappingUsageRef.set(usage);
            doCountDown.run();
        }, listener::onFailure);