docs(kafka_producer): update ZH translation of field (rv5.0)

Fixes https://emqx.atlassian.net/browse/EMQX-9411

lib-ee/emqx_ee_bridge/i18n/emqx_ee_bridge_kafka.conf

@@ -62,7 +62,7 @@ emqx_ee_bridge_kafka {
     mqtt_topic {
         desc {
             en: "MQTT topic or topic as data source (bridge input).  Should not configure this if the bridge is used as a rule action."
-            zh: "指定 MQTT 主题作为桥接的数据源。 若该桥接用于规则的动作，则必须将该配置项删除。"
+            zh: "桥接指定 MQTT 主题数据，也可以留空由规则动作指定数据源。"
         }
         label {
             en: "Source MQTT Topic"