Fix spec violations in current_day_indicator_spec

What does this MR do and why?

In regards of epic &5102, this MR fixes the following spec violations in ee/spec/frontend/roadmap/components/current_day_indicator_spec.js #391006 (closed):

• setData usage

How to set up and validate locally

Run tests:

yarn jest ee/spec/frontend/roadmap/components/current_day_indicator_spec.js

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.