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/qa/profile/src/javaRestTest/java/org/elasticsearch/xpack/security/profile/ProfileIT.java
.build();
    }
    public void testActivateProfile() throws IOException {
        final Map<String, Object> activateProfileMap = doActivateProfile();
        final String profileUid = (String) activateProfileMap.get("uid");
        final Map<String, Object> profile1 = doGetProfile(profileUid);
        assertThat(profile1, equalTo(activateProfileMap));
    }
    @SuppressWarnings("unchecked")
    public void testProfileHasPrivileges() throws IOException {
        final Map<String, Object> activateProfileMap = doActivateProfile();
        final String profileUid = (String) activateProfileMap.get("uid");
        final Request profileHasPrivilegesRequest = new Request("POST", "_security/profile/_has_privileges");
        profileHasPrivilegesRequest.setJsonEntity("""
            {
              "uids": ["some_missing_profile", "%s"],
              "privileges": {
                "index": [
                  {
                    "names": [ "rac_index_1" ],
                    "privileges": [ "read" ]
                  }
                ],
                "cluster": [
                  "cluster:monitor/health"
                ]
              }
            }""".formatted(profileUid));
        final Response profileHasPrivilegesResponse = adminClient().performRequest(profileHasPrivilegesRequest);
        assertOK(profileHasPrivilegesResponse);