we shouldnt allow passing an `openai` object in

[paperclover]

point is to abstract away the package. you shouldnt even have to think about these other packages. this is a regression from 0.4 which let you just take a base url and api key.

export interface OpenAICompletionsAdapterOptions<TModel extends string> {
  model: TModel;
  name: string;
  client: OpenAICompletionsClient; // caller passes in an `openai` instance
  parallelToolCalls?: boolean;
  supportedMimeTypes?: string[];
  pdfSupport?: OpenAICompletionsPdfSupport<TModel>;
  extraRequestBody?: OpenAICompletionsExtraRequestBody<TModel>;
}