Forbid Sidekiq scheduling in transactions

What does this MR do?

This patches Sidekiq so jobs can't be scheduled inside a transaction.

Does this MR meet the acceptance criteria?

• Changelog entry added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #27233 (closed)