Fix url key of createFileOutput options for streaming

[sitatec]

Currently, if you try to stream files you get a FileOutput instance in the following state:

FileOutput {
  locked: false,
  [state]: 'errored',
  [supportsBYOB]: false,
  [length]: undefined
}

This is because a { data, fetch } object is passed to createFileOutput, which expects a { url, fetch } object.

I also noticed that FileOutput is always used for streaming, so I added the useFileOutput option to the *stream function and set the value of Replicate.useFileOutput as default.

[u6516024155-coder]

Patrycja

[u6516024155-coder]

Super aplikacja😘

[rovo89]

I have just spend at least two hours trying to find out what I'm doing wrong, trying to write the output to a file. Besides the fact that ServerSentEvent.data is a string and needs to be converted to a ReadableStream or FileOutput first, the crucial point was the wrong call of createFileOutput() that is fixed with this PR.

@zeke Could you merge at least this part of the suggested change? Not sure about the other half and the types, but for the wrong call there is no workaround. Thanks!