Bug 27277: Queued Vs Enqueued

Bug 27277: Queued Vs Enqueued

This patch changes "Enqueued on", "Started on", and "Ended on" to
"Queued", "Started", and "Ended" respectively on the bacground jobs
page.

Task plan:
1. Navigate to the background jobs page
2. Ensure the spelling change, and that the spelling is correct.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit df71a27a667936ea5e2ef96f0a31b45179ce53c7)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>