[META] Improve model interface parsing

[ohltyler]

Current logic is very basic and has some hardcoded paths for parsing out JSON schema from a model interface (see utils helper fns). This can be improved upon in several different ways:

• Optional field support Support optional model inputs #695
• Boolean combination support
• nested interface support: as more models are supported and as the interfaces can become more complex, explore how to support more deeply nested interfaces. Currently, the inputs/outputs are assumed to be single lists of fields with basic values. Many LLMs, however, can take in complex arrays as inputs, and output complex arrays as responses. Having a more user-friendly way for constructing the input and output transforms can be helpful.