Fixed icon not updating on Ember from AdminX (#18374)

refs
https://www.notion.so/ghost/df5bdea8f7ea4aca9d25eceb6a1bf34c?v=be2f15b6b58b4c27a0e11374282bead0&p=bafc80a9ad644fb18fe338f89500ff36&pm=s

- we now reload ember's settings data when settings data updated, to
keep certain data synced, such as the icon in the sidebar.

---

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### <samp>🤖 Generated by Copilot at 572a569</samp>

Refactor settings component to use Ember Octane and reload settings
model after saving. This improves the UI and code quality of the
`admin-x` component.

ghost/admin/app/components/admin-x/settings.js

@@ -324,6 +324,8 @@ export default class AdminXSettings extends Component {
         if (dataType === 'SettingsResponseType') {
             // Blog title is based on settings, but the one stored in config is used instead in various places
             this.config.blogTitle = response.settings.find(setting => setting.key === 'title').value;
+
+            this.settings.reload();
         }
 
         if (dataType === 'TiersResponseType') {