Update feature flags and screenshot (#1143)

* Update ui.mdx

* Update sidebar screenshot

* Update ui.mdx

src/docs/delightful-developer-metrics/ui.mdx

@@ -12,14 +12,17 @@ In order to plot your metrics, we have developed a prototype user interface, whi
 The first step towards using the UI is to enable it, since right now it’s feature flagged. 
 These two flags need to be turned on:
 
-- `organizations:custom-metrics` - controls ingestions and UI
-- `organizations:ddm-ui` - controls UI
+- `organizations:custom-metrics` - ingestion and UI
+- `organizations:ddm-ui` - UI
+- `organizations:metric-meta` - sample events and code locations
+- `organizations:use-metrics-layer-in-alerts` - custom metric alerts
 
-See our guide on [feature flags](/feature-flags/) to learn how to do that. Sentry employees can opt in organizations like [this](https://github.com/getsentry/sentry-options-automator/pull/499).
+
+See our guide on [feature flags](/feature-flags/) to learn how to do that.
 
 Once you have the feature flag enabled you will magically see a new sidebar item called Metrics and now the fun begins!
 
-![Metrics Sidebar](/images/sidebar.png)
+![Metrics Sidebar](/images/sidebar2.png)
 
 ## Using the UI