File permissions can't have full accesss

Describe the bug

Unable to set

Files are created as 755 due to umask.

To Reproduce

add to config: file_permission 777

Expected behavior

files should be created with full permissions

Your Environment

- Fluentd version: v1.16.6-debian-1.0
- Operating system:GNU/Linux
- Kernel version:3.10.0-1160.76.1.el7.x86_64

Your Configuration

<system>
  file_permission 777
</system>

<source>
  @type forward
  port 24224
  bind 0.0.0.0
</source>

<match **>
  @type copy
  
  <store>
  @type file
    path /app/log/webui-testing/webui-debug-log3
    append true
    format out_file
    <buffer>
      path /app/buffer/webui/webui-debug-buffer
      flush_interval 5s
      flush_mode interval
      chunk_limit_size 512m
      total_limit_size 1g
      overflow_action block
      @type file
    </buffer>
  </store>
</match>

Your Error Log

NO error message,

Files are created with r-x permissions (755) due to the default umask.

Additional context

If changing the permissions is not possible how can we change the default umask?