replace null with undefined for array

5 jobs for unlink-stats in 3 minutes and 48 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test Build Static
passed #304742
Test_N_Build:review

00:02:33

 
  Build Docker Images
passed #304743
Nginx:review

00:00:55

 
  Deploy
passed #304744
Feature:EHK-HH

00:00:09

passed #304745
Review:WP-HX

00:00:18

manual #304746
allowed to fail manual
stop_review