[enhancement](log)Updated the default setting of sys_log_mode in fe.c…

…onf for better performance (apache#37793)

## Proposed changes

<!--Describe your changes.-->
Updated the default setting of `sys_log_mode` in `fe.conf` from `NORMAL`
to `ASYNC` for better performance.

conf/fe.conf

@@ -64,7 +64,7 @@ arrow_flight_sql_port = -1
 # INFO, WARN, ERROR, FATAL
 sys_log_level = INFO
 # NORMAL, BRIEF, ASYNC
-sys_log_mode = NORMAL
+sys_log_mode = ASYNC
 # sys_log_roll_num = 10
 # sys_log_verbose_modules = org.apache.doris
 # audit_log_dir = $LOG_DIR

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

@@ -70,14 +70,14 @@ public class Config extends ConfigBase {
     @ConfField(description = {"FE 日志的级别", "The level of FE log"}, options = {"INFO", "WARN", "ERROR", "FATAL"})
     public static String sys_log_level = "INFO";
 
-    @ConfField(description = {"FE 日志的输出模式，其中 NORMAL 为默认的输出模式，日志同步输出且包含位置信息，"
-            + "BRIEF 模式是日志同步输出但不包含位置信息，ASYNC 模式是日志异步输出且不包含位置信息，三种日志输出模式的性能依次递增",
-            "The output mode of FE log, and NORMAL mode is the default output mode, which means the logs are "
-                    + "synchronized and contain location information. BRIEF mode is synchronized and does not contain"
-                    + " location information. ASYNC mode is asynchronous and does not contain location information."
-                    + " The performance of the three log output modes increases in sequence"},
+    @ConfField(description = {"FE 日志的输出模式，其中 NORMAL 模式是日志同步输出且包含位置信息，BRIEF 模式是日志同步输出"
+                    + "但不包含位置信息，ASYNC 模式为默认的输出模式，是日志异步输出且不包含位置信息，三种日志输出模式的性能依次递增",
+            "The output mode of FE log, and NORMAL mode means the logs are synchronized and contain location "
+                    + "information. BRIEF mode is synchronized and does not contain location information. "
+                    + "ASYNC mode is the default output mode, which is asynchronous and does not contain "
+                    + "location information. The performance of the three log output modes increases in sequence"},
             options = {"NORMAL", "BRIEF", "ASYNC"})
-    public static String sys_log_mode = "NORMAL";
+    public static String sys_log_mode = "ASYNC";
 
     @ConfField(description = {"FE 日志文件的最大数量。超过这个数量后，最老的日志文件会被删除",
             "The maximum number of FE log files. After exceeding this number, the oldest log file will be deleted"})