Improve usage analytics configuration UX (#1585)

- Add sidebar link to correct config section.
- Update example identifier to match actual generated identifiers

frontend/components/forms/admin/AppConfigForm/AppConfigForm.jsx

@@ -223,7 +223,7 @@ class AppConfigForm extends Component {
     }
 
     const json = {
-      anonymous_identifier: 1,
+      anonymous_identifier: "wmTH972f06USpahr41LHpgLKAhgZL",
       fleet_version: "x.x.x",
       hosts_enrolled_count: 12345,
     };
@@ -519,7 +519,7 @@ class AppConfigForm extends Component {
               <a id="usage-stats">Usage statistics</a>
             </h2>
             <p className={`${baseClass}__section-description`}>
-              Help us improve Fleet by sending us anonymous usage statistics.
+              Help improve Fleet by sending anonymous usage statistics.
               <br />
               <br />
               This information helps our team better understand feature adoption

frontend/pages/admin/AppSettingsPage/AppSettingsPage.jsx

@@ -81,6 +81,9 @@ class AppSettingsPage extends Component {
               <li>
                 <a href="#agent-options">Global agent options</a>
               </li>
+              <li>
+                <a href="#usage-stats">Usage statistics</a>
+              </li>
               <li>
                 <a href="#advanced-options">Advanced options</a>
               </li>