Use brave_domains for Origin buy URL instead of hardcoding (#33838)

browser/resources/settings/brave_origin_page/brave_origin_onboarding.ts

@@ -7,6 +7,7 @@ import 'chrome://resources/cr_elements/cr_button/cr_button.js';
 import '../settings_shared.css.js';
 
 import {I18nMixin, I18nMixinInterface} from 'chrome://resources/cr_elements/i18n_mixin.js';
+import {loadTimeData} from 'chrome://resources/js/load_time_data.js';
 import {PolymerElement} from 'chrome://resources/polymer/v3_0/polymer/polymer_bundled.min.js';
 
 import {BaseMixin} from '../base_mixin.js';
@@ -33,7 +34,7 @@ export class SettingsBraveOriginOnboardingElement extends
 
   private onBuyNowClick_() {
     window.open(
-        'https://account.brave.com/?intent=checkout&product=origin&mtm_campaign=browser-settings',
+        loadTimeData.getString('braveOriginBuyUrl'),
         '_blank',
         'noopener');
   }

browser/ui/webui/brave_settings_ui.cc

@@ -12,6 +12,8 @@
 #include "base/check_deref.h"
 #include "base/compiler_specific.h"
 #include "base/feature_list.h"
+#include "base/strings/strcat.h"
+#include "brave/brave_domains/service_domains.h"
 #include "brave/browser/brave_account/brave_account_service_factory.h"
 #include "brave/browser/brave_origin/brave_origin_service_factory.h"
 #include "brave/browser/email_aliases/email_aliases_service_factory.h"
@@ -284,6 +286,13 @@ void BraveSettingsUI::AddResources(content::WebUIDataSource* html_source,
                           brave_origin::IsBraveOriginEnabled());
   html_source->AddBoolean("isBraveOriginBrandedBuild",
                           BUILDFLAG(IS_BRAVE_ORIGIN_BRANDED));
+  html_source->AddString(
+      "braveOriginBuyUrl",
+      base::StrCat(
+          {"https://",
+           brave_domains::GetServicesDomain(
+               "account", brave_domains::ServicesEnvironment::STAGING),
+           "/?intent=checkout&product=origin&mtm_campaign=browser-settings"}));
   html_source->AddBoolean("isTreeTabsFlagEnabled",
                           base::FeatureList::IsEnabled(tabs::kBraveTreeTab));
   html_source->AddString("braveSearchEngineName",