ci: Check all build jobs' status in FVP summary report

The status of only the first 20 build jobs was being checked to infer
pipeline success. This is because of a cap in the GitLab job get API.
It was causing some pipelines with build job failures to appear
green on the FVP summary report.

Fix this by checking all pages returned by the GitLab job API as
opposed to just the first.

Signed-off-by: Debbie Martin <Debbie.Martin@arm.com>