Removed extra warning

The feature flag warning is not needed

doc/user/admin_area/analytics/usage_trends.md

@@ -12,9 +12,6 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 > - It's enabled on GitLab.com.
 > - It's recommended for production use.
 
-WARNING:
-This feature might not be available to you. Check the **version history** note above for details.
-
 Usage Trends gives you an overview of how much data your instance contains, and how quickly this volume is changing over time.
 Usage Trends data refreshes daily.