Port PR from PBS-Java: Magnite adapter: Rebrand Rubicon adapter into Magnite adapter

[cross-repo-issue-creation]

A PR was merged over on PBS-Java

• Magnite adapter: Rebrand Rubicon adapter into Magnite adapter prebid-server-java#4573
• timestamp: 2026-07-27T17:14:08Z

[bsardo]

Magnite to contribute this.