Custom SLI for Verify:Testing endpoints

What does this MR do and why?

Set custom SLI for the following:

Endpoint	New target duration	urgency
GET /api/projects/:id/pipelines/:pipeline_id/test_report	5 seconds	low
POST /api/jobs/:id/artifacts	5 seconds	low
GET /api/projects/:id/jobs/artifacts/:ref_name/raw/*artifact_path	5 seconds	low
POST /api/jobs/:id/artifacts/authorize	3.5 seconds	low
GET /api/jobs/:id/artifacts	2.5 seconds	low

Screenshots or screen recordings

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How to set up and validate locally

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

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.

Related to #345567 (closed)