[Fix](auth) fix some problem of skip_localhost_auth_check in FE config #18996

docs/en/docs/admin-manual/privilege-ldap/user-privilege.md

@@ -236,7 +236,7 @@ ADMIN_PRIV and GRANT_PRIV have the authority of **"grant authority"** at the sam
 
 5. Forget passwords
 
-	If you forget your password and cannot log in to Doris, you can add `skip_localhost_auth_check` in fe config so that logging to Doris without a password in localhost.
+	If you forget your password and cannot log in to Doris, you can add `skip_localhost_auth_check` in fe config and restart FE so that logging to Doris without a password in localhost.
 
 	`skip_localhost_auth_check = true`
 

docs/zh-CN/docs/admin-manual/privilege-ldap/user-privilege.md

@@ -228,7 +228,7 @@ ADMIN_PRIV 和 GRANT_PRIV 权限同时拥有**授予权限**的权限，较为
 
 5. 忘记密码
 
-   如果忘记了密码无法登陆 Doris，可以在 FE 的 config 文件中添加 `skip_localhost_auth_check` 参数，从而无密码在本机登陆 Doris：
+   如果忘记了密码无法登陆 Doris，可以在 FE 的 config 文件中添加 `skip_localhost_auth_check` 参数，并且重启FE，从而无密码在本机通过localhost登陆 Doris：
 
    `skip_localhost_auth_check = true`
 

fe/fe-common/src/main/java/org/apache/doris/common/Config.java

@@ -2147,7 +2147,7 @@ public class Config extends ConfigBase {
      * If true, auth check will be disabled. The default value is false.
      * This is to solve the case that user forgot the password.
      */
-    @ConfField(mutable = true)
+    @ConfField(mutable = false)
     public static boolean skip_localhost_auth_check  = false;
 }