Add ingress_modsecurity feature flag to usage ping

Since this feature flag is disabled by default this allows us to track
how many instances have enabled the feature

Related to https://gitlab.com/gitlab-org/gitlab/issues/32358

changelogs/unreleased/32358-add-modsec-feature-flag-to-usage-ping.yml

+---
+title: Add modsecurity feature flag to usage ping
+merge_request: 20194
+author:
+type: added

lib/gitlab/usage_data.rb

@@ -134,7 +134,8 @@ module Gitlab
           prometheus_metrics_enabled: Gitlab::Metrics.prometheus_metrics_enabled?,
           reply_by_email_enabled: Gitlab::IncomingEmail.enabled?,
           signup_enabled: Gitlab::CurrentSettings.allow_signup?,
-          web_ide_clientside_preview_enabled: Gitlab::CurrentSettings.web_ide_clientside_preview_enabled?
+          web_ide_clientside_preview_enabled: Gitlab::CurrentSettings.web_ide_clientside_preview_enabled?,
+          ingress_modsecurity_enabled: Feature.enabled?(:ingress_modsecurity)
         }
       end
 

spec/lib/gitlab/usage_data_spec.rb

@@ -84,6 +84,7 @@ describe Gitlab::UsageData do
         influxdb_metrics_enabled
         prometheus_metrics_enabled
         web_ide_clientside_preview_enabled
+        ingress_modsecurity_enabled
       ))
     end