ObjectRenderer doesn't crash when no objects to cache with Rails.cache.read_multi

What does this MR do?

Avoid calls to Rails.cache.read_multi without cache keys so it doesn't raise an exception

What are the relevant issue numbers?

Closes #19766 (closed)

Does this MR meet the acceptance criteria?

• CHANGELOG entry added. I considered is not needed is a fix over a RC
• [ ] Documentation created/updated
• [ ] API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together