Fix order-dependent GraphQL Work Items update spec

What does this MR do and why?

Closes #368500 (closed).

Verified via:

bin/rspec ./spec/requests/api/graphql/mutations/work_items/update_spec.rb[1:2:8:1:1:1,1:2:8:1:2:2:1] --seed 14775

See #368500 (comment 1035172347)

Refs #337399 (closed)

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