Code generation: Top-level array response is unsupported

### Subject of the issue

While exposing a new route in SDKs, code generation fails to produce working code. Provided we agree the OAS definition is valid, the ticket's request is to modify _generator_ to support the use case.

It appears the problem is specific to returning a top-level array response. The affected route is _"/v2/applications/{application-id}/boxes"_ in https://github.com/algorand/go-algorand/blob/feature/avm-box/daemon/algod/api/algod.oas2.json.

### Your environment

N/A

### Steps to reproduce

Here's a PR illustrating the

1. Configure environment locally as documented in https://github.com/algorand/go-algorand-sdk/pull/340#issuecomment-1175246907.
2. Generate Java/Go SDK code changes and observe broken compilation.

### Expected behaviour

_generator_ produces Java + Go SDK changes that compile + implement the spec.

### Actual behaviour

Here's a PR illustrating the as-is behavior: https://github.com/algorand/go-algorand-sdk/pull/340 .