branch-2.1: [fix](config) fe config sync_image_timeout_second should not be masterOnly #43954 (#44384)

Cherry-picked from #43954

Co-authored-by: nsn_huang <38585669+nsnhuang@users.noreply.github.com>
Co-authored-by: huangwenbo04 <huangwenbo04@meituan.com>

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

@@ -2585,7 +2585,7 @@ public class Config extends ConfigBase {
     })
     public static boolean ignore_unknown_metadata_module = false;
 
-    @ConfField(mutable = true, masterOnly = true, description = {
+    @ConfField(mutable = true, description = {
             "从主节点同步image文件的超时时间，用户可根据${meta_dir}/image文件夹下面的image文件大小和节点间的网络环境调整，"
                     + "单位为秒，默认值300",
             "The timeout for FE Follower/Observer synchronizing an image file from the FE Master, can be adjusted by "