Eliminate usage of lambdas when translating VSA stage data

What does this MR do?

This is a small refactor MR where we move a confusing hash constant with lambdas to a class method. Related conversation: !16240 (comment 219818719)

No user facing changes.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Closes #32571 (closed)