Translate value in approver dropdown options in MR

Issue #217036 (closed)

What does this MR do?

This MR translates the value in the filter-dropdown-item. This will also make it consistent with another similar file approved-by dropdown:

• https://gitlab.com/gitlab-org/gitlab/blob/27faa01048df44d48943f6053c50c2c297256b8b/ee/app/views/shared/issuable/_approved_by_dropdown.html.haml#L3
• https://gitlab.com/gitlab-org/gitlab/blob/27faa01048df44d48943f6053c50c2c297256b8b/ee/app/views/shared/issuable/_approved_by_dropdown.html.haml#L6

Closes #217036 (closed)