[Решено] remove the notice warning error on the backend console

Background of the issue:
I am trying to remove the notice warning error on the backend console. This was done before by a WPML support agent by removing a line of code, but I forgot where it is. The issue can be seen at скрытая ссылка.

Symptoms:
I expected to see a normal WordPress backend without these errors, but instead, I got a screen with errors.

Questions:
Where is the line of code that needs to be removed to fix the notice warning error?
How can I remove the notice warning error on the backend console?