Consider changing configuration to not pretty-print JSON by default

### Motivation

When debugging an issue with a solar inverter, I bumped into this default:

https://github.com/apple/swift-openapi-runtime/blob/e5b0de7221dd1a0c9b9a6de9afdbe06f3e46a24f/Sources/OpenAPIRuntime/Conversion/Configuration.swift#L165

As it turns out, the issue with this inverter was that it did not handle pretty-printed JSON. This cost me about 30 minutes of debugging time as I tried to root-cause why the curl equivalent of my command worked, but the swift-openapi-generator equivalent didn't.

In general, I was surprised to see swift-openapi-generator defaulting to pretty-printing JSON. While the default of `sortedKeys` makes some sense to me (certain tests are easier to write), the pretty-printed default seems to me to have more downsides with fewer obvious upsides. Most notably, it diverges from common practice in JSON-encoding libraries, which tend to default to minified JSON and require user action to prettify it.

### Proposed solution

It seems to me that the community should at least consider whether the default behaviour here should be flipped.

### Alternatives considered

_No response_

### Additional information

_No response_

Start by reading Sources/OpenAPIRuntime/Conversion/Configuration.swift around line 165, where the JSON configuration referenced in the issue is defined. Review the surrounding configuration and the discussion before determining whether pretty-printing should remain the default. Done means the project has a documented decision on the default behavior and any resulting changes are covered by the relevant project checks.

Written by the indexing model from the issue text.