DEV: Remove deprecated search_tokenize_chinese_japanese_korean setting (#30549)

It was supposed to be removed ~3 years ago (there was [a migration](b4f0a8748d/db/migrate/20220126052157_change_segment_cjk_site_setting.rb) already)

spec/requests/admin/site_settings_controller_spec.rb

@@ -238,13 +238,19 @@ RSpec.describe Admin::SiteSettingsController do
       end
 
       it "works for deprecated settings" do
-        put "/admin/site_settings/search_tokenize_chinese_japanese_korean.json",
-            params: {
-              search_tokenize_chinese_japanese_korean: true,
-            }
+        deprecated_test = "#{Rails.root}/spec/fixtures/site_settings/deprecated_test.yml"
+        SiteSetting.load_settings(deprecated_test)
 
-        expect(response.status).to eq(200)
-        expect(SiteSetting.search_tokenize_chinese).to eq(true)
+        stub_const(
+          SiteSettings::DeprecatedSettings,
+          "SETTINGS",
+          [["old_one", "new_one", true, "3.0"]],
+        ) do
+          put "/admin/site_settings/old_one.json", params: { old_one: true }
+
+          expect(response.status).to eq(200)
+          expect(SiteSetting.new_one).to eq(true)
+        end
       end
 
       it "throws an error when the parameter is not a configurable site setting" do