Spec test for error tracking Web UI is not stable

Summary

Spec test for error tracking Web UI is still not stable.

Had a similar breaking described in #202678 (closed) and then fixed it in !24718 (merged).

Steps to reproduce

Run the pipeline for gitlab-org/gitlab on the 1st day of the month.

Example Project

• Screenshot: https://gitlab.com/gitlab-org/gitlab/-/jobs/455070226/artifacts/file/tmp/capybara/screenshot_2020-03-01-06-58-11.041.png
• Captured HTML: https://gitlab.com/gitlab-org/gitlab/-/jobs/455070226/artifacts/file/tmp/capybara/screenshot_2020-03-01-06-58-11.041.html

What is the current bug behavior?

JS handles 2020-02-01 as 4 week ago on 2020-03-01 (the testing day) while Ruby generates 2020-02-01 as 1 month ago of 2020-03-01 (the testing day).

What is the expected correct behavior?

TBD

Possible fixes

Test with 32 days ago instead of 1 month ago.