Fix spec violations in dashboard_spec.js

What does this MR do and why?

This MR implements #391129 (closed).

It fixes spec violations in ee/spec/frontend/operations/components/dashboard/dashboard_spec.js

Screenshots or screen recordings

No user-facing changes.

How to set up and validate locally

1. Run yarn jest ee/spec/frontend/operations/components/dashboard/dashboard_spec.js or just check the pipeline

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #391129 (closed)