Create labels_as_hash_ concern

What does this MR do?

Places labels_as_hash logic into a concern.

What are the relevant issue numbers?

Closes #48930 - Tech debt: Extract labels_as_hash logic into a concern

Does this MR meet the acceptance criteria?

• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• EE specific content should be in the top level /ee folder