chore: update server-changes to include global flags tab

Author: nicktrn

.server-changes/admin-feature-flags-dialog.md

@@ -3,4 +3,4 @@ area: webapp
 type: feature
 ---
 
-Add admin UI dialog for viewing and editing org-level feature flag overrides.
+Add admin UI for viewing and editing feature flags (org-level overrides and global defaults).