CI: github: fix tag listing by implementing proper API pagination

CI: github: fix tag listing by implementing proper API pagination

The GitHub API silently caps per_page at 100, so passing per_page=200
was silently returning at most 100 tags. AWS-LC-FIPS tags appear late
in the list, causing version detection to fail.

Replace the single-page fetch in get_all_github_tags() with a loop that
iterates all pages.

Could be backported in previous branches.