docs: Update apps/emqx/i18n/emqx_schema_i18n.conf

Co-authored-by: Ivan Dyachkov <dev@dyachkov.org>

apps/emqx/i18n/emqx_schema_i18n.conf

@@ -46,7 +46,7 @@ emqx_schema {
 
   overload_protection_backoff_delay {
     desc {
-        en: "When at high load, some unimportant tasks could be delayed for execution, here set the duration."
+        en: "The maximum duration of delay for background task execution during high load conditions."
         zh: "高负载时，一些不重要的任务可能会延迟执行，在这里设置允许延迟的时间。"
     }
     label {