Protect group overview usage ping w/ feature flag

user_preferences key is includes into system usage
data only if group_overview_security_dashboard
feature flag is enabled; see
https://gitlab.com/gitlab-org/gitlab-ee/issues/7048

ee/lib/ee/gitlab/usage_data.rb

@@ -92,10 +92,14 @@ module EE
       # the base key part after a corresponding User model attribute, use its possible values as suffix values.
       override :user_preferences_usage
       def user_preferences_usage
-        super.merge(
-          group_overview_details: count(::User.active.group_view_details),
-          group_overview_security_dashboard: count(::User.active.group_view_security_dashboard)
-        )
+        super.tap do |user_prefs_usage|
+          if ::Feature.enabled?(:group_overview_security_dashboard)
+            user_prefs_usage.merge!(
+              group_overview_details: count(::User.active.group_view_details),
+              group_overview_security_dashboard: count(::User.active.group_view_security_dashboard)
+            )
+          end
+        end
       end
 
       override :system_usage_data

ee/spec/lib/gitlab/usage_data_spec.rb

@@ -100,12 +100,17 @@ describe Gitlab::UsageData do
       expect(count_data[:sast_jobs]).to eq(1)
     end
 
-    it 'gathers security-related preferences usage data' do
+    it 'gathers group overview preferences usage data' do
       expect(subject[:counts][:user_preferences]).to eq(
         group_overview_details: User.active.count - 2, # we have exactly 2 active users with security dashboard set
         group_overview_security_dashboard: 2
       )
     end
+
+    it 'does not gather group overview preferences usage data when the feature is disabled' do
+      stub_feature_flags(group_overview_security_dashboard: false)
+      expect(subject[:counts].keys).not_to include(:user_preferences)
+    end
   end
 
   describe '#features_usage_data_ee' do

lib/gitlab/usage_data.rb

@@ -95,8 +95,11 @@ module Gitlab
           }
           .merge(services_usage)
           .merge(approximate_counts)
-          .merge(user_preferences: user_preferences_usage)
-        }
+        }.tap do |data|
+          if Feature.enabled?(:group_overview_security_dashboard)
+            data[:counts][:user_preferences] = user_preferences_usage
+          end
+        end
       end
       # rubocop: enable CodeReuse/ActiveRecord
 

spec/lib/gitlab/usage_data_spec.rb

@@ -129,6 +129,11 @@ describe Gitlab::UsageData do
       ))
     end
 
+    it 'does not gather user preferences usage data when the feature is disabled' do
+      stub_feature_flags(group_overview_security_dashboard: false)
+      expect(subject[:counts].keys).not_to include(:user_preferences)
+    end
+
     it 'gathers projects data correctly' do
       count_data = subject[:counts]