Port PR from PBS-Go: Dockerfile vulnerabilities fixes

[cross-repo-issue-creation[bot]]

A PR was merged over on PBS-Go

• https://github.com/prebid/prebid-server/pull/4270
• timestamp: 2025-03-24T17:07:37Z

[Net-burst]

This is probably valid for Prebid Server Java. At least the part of running using an unprivileged uid/gid. However, there is a caveat that this should probably go in PBS 4.0 as this might break deploys wherethe Prebid Server is expected to write into a mount.

[bsardo]

@Net-burst do you want to add this to the 4.0 issue?