Determine if and how `link_class_info` will be used in the submission schema

[mslarae13]

slot link_class_info has no guidance or examples.

criteria for completion

• [x] identify how the slot has been used (if at all) in the past, @turbomam provide a query of NCBI?
• [ ] Update nmdc.yaml (or mixs.yaml?) to add more context and examples
• [ ] update NMDC submission portal to match schema slot usage (Mike)