Refactor secondsToMilliseconds to make this available for importing

Summary

Refactor to make the seconds to milliseconds function available for use within components. This function: https://gitlab.com/gitlab-org/gitlab/blob/0d753e479d2a7dedd91ef251f8bd863f16b32b71/app/assets/javascripts/monitoring/utils.js#L4 could be useful to be exposed for use in components. An example of that can be seen in !18255 (merged).

Improvements

• Simply export this function so it's available.

Risks

• No real risks.

Involved components

• app > assets > javascripts > pipelines > stores > test_reports > utils.js