Fix bug where zentao issues could not render due to missing id

What does this MR do and why?

Page with bug:

http://localhost:3000/my-dev/zentao-integration/-/integrations/zentao/issues

Browser error log:

MR introducing bug:

!74180 (merged)

Specific location:

https://gitlab.com/gitlab-org/gitlab/-/blame/master/ee/app/assets/javascripts/integrations/zentao/issues_list/graphql/fragments/zentao_label.fragment.graphql#L2

Cause of the bug

zentao_label.fragment.graphql adds new fields id, but the backend does not provide this field.

How to fix

Add id field to user type of ZentaoSerializers.