chore: Remove legacy Sipi upload mechanism (DEV-4260)

[siers]

Pull Request Checklist

Task Description/Number

Issue Number: DEV-

PR Type

• build/chore: maintenance tasks (no production code change)
• docs: documentation changes (no production code change)
• feat: represents new features
• fix: represents bug fixes
• perf: performance improvements
• refactor: represents production code refactoring
• test: adding or refactoring tests (no production code change)
• deprecated: Deprecation warning (ideally referencing a migration guide)

Basic requirements for bug fixes and features

• Tests for the changes have been added
• Docs have been added / updated

Does this PR introduce a breaking change?

• Yes

[linear]

DEV-4260 Remove feature to ingest assets with Sipi

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 17.88%. Comparing base (6ebe8e7) to head (f10a5d1).
Report is 127 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #3414       +/-   ##
===========================================
- Coverage   83.04%   17.88%   -65.16%     
===========================================
  Files         290      304       +14     
  Lines       23087    22760      -327     
===========================================
- Hits        19172     4071    -15101     
- Misses       3915    18689    +14774     

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