Fix: issuable list item time locale issue

What does this MR do and why?

Our current issuable list item contains untranslated time section, and in the code it uses the mixin from mixin/timeago but it did not use the method exposed by the mixin for formatting the time. In this MR, I replaced the format method with the mixin exposed method.

/cc @prajnamas @qk44077907 @orozot

Fix: issuable list item time locale issue

• Use locale format the time item.

Changelog: fixed

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

• Pre-request: set your preferred language to any language other than English

1. Go to any project's issue list.
2. Observe the issuable list item.

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.