Change available sampling parameters depending on API

[mkbehr]

As of today, we have frequency penalty and presence penalty parameters that can be passed through to Gemini and OpenAI APIs, but they'll be ignored for Ollama. That could confuse experimenters. The confusion could get worse if we ever add support for more complicated parameters with less-broad support (e.g. mirostat, min p). Ideally we'd note which APIs support which parameters, and only display applicable ones.