fix types for the `run()` method

[gianpaj]

I shouldn't have to write all of this code.

interface ReplicateOutput {
  url: () => string;
  blob: () => Promise<Blob>;
}
interface ReplicateError {
  error?: string;
}
type ReplicateResponse = ReplicateOutput | ReplicateError;

const output = (await replicate.run(
  model,
  {
    input,
  },
  onProgress,
)) as ReplicateResponse;

const outputUrl = (output as ReplicateOutput).url();

const audioBuffer = await (output as ReplicateOutput).blob();