fix: Consider `scope` an ArrayAttribute in PipelineJobManager

List query params like 'scope' were not being handled correctly for
pipeline/jobs endpoint.
This change ensures multiple values are appended with '[]', resulting in
the correct URL structure.

Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com>

---

Background:
If one queries for pipeline jobs with `scope=["failed", "success"]`

One gets:
GET /api/v4/projects/176/pipelines/1113028/jobs?scope=success&scope=failed

But it is supposed to get:
GET /api/v4/projects/176/pipelines/1113028/jobs?scope[]=success&scope[]=failed

The current version only considers the last element of the list argument.

Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com>