fix:SDK-2025 -- [Android] Remove unused code

[gdeluna-branch]

Reference

SDK-2025 -- [Android] Remove unused code

Description

Removing more code that has fallen into disuse.

• ServerRequestRegisterClose
• FB app link may still be used, researching.
• Referral/Content URL builders
• Unused NetworkCallback interface
• Deprecated request paths
  • Credits
• Defunct CI scripts
  • GitLab
• A notice for a bug that has since been fixed
  • https://bugs.chromium.org/p/chromium/issues/detail?id=484815
  • https://bugs.chromium.org/p/chromium/issues/detail?id=638672

Testing Instructions

Run through a test app, especially opening and closing as we're removing the post. No behavior should change.

Risk Assessment [LOW]

• [✅] I, the PR creator, have tested — integration, unit, or otherwise — this code.

Reviewer Checklist (To be checked off by the reviewer only)

• JIRA Ticket is referenced in PR title.
• Correctness & Style
  • Conforms to AOSP Style Guides
  • Mission critical pieces are documented in code and out of code as needed.
• Unit Tests reviewed and test issue sufficiently.
• Functionality was reviewed in QA independently by another engineer on the team.

cc @BranchMetrics/saas-sdk-devs for visibility.