fix(download): Fix download url by reverting change

[thejaminator]

Fixes #196, and probably #185 and #183

This MR reverts the change in https://github.com/openai/openai-python/pull/146/files#r1084884786 so that the requests hit the /content url of the api again.

cc @Andrew-Chen-Wang @ddeville

To reproduce, on the older openai==0.25.0
`

openai api fine_tunes.results -i <job_id_here>

You'll get the output of the actual CSV file

E.g.

step,elapsed_tokens,elapsed_examples,training_loss,training_sequence_accuracy,training_token_accuracy
1,22048,32,0.011019098009307718,0.0,0.0
1,32288,32,0.007613447834811513,0.0,0.0

On the current openai==0.26.2

You get instead

{
"object": "file",
"id": "file-66NnpqAXzw3In27fROPIU03P",
"purpose": "fine-tune-results",
"filename": "compiled_results.csv",
"bytes": 386756,
"created_at": 1674504271,
"status": "processed",
"status_details": null
}

[Andrew-Chen-Wang]

%s and f strings have different formatting rules, but good catch on the url path! Might've accidentally deleted it

[thejaminator]

%s and f strings have different formatting rules, but good catch on the url path! Might've accidentally deleted it

interesting. whats the difference?

[hallacy]

(will merge once the above conversation is resolved)

[Andrew-Chen-Wang]

Ref: https://stackoverflow.com/questions/5082452/string-formatting-vs-format-vs-f-string-literal

It's simply because of tuples and a few other things. (Take a look at flynt). I don't think it's applicable in this case in retrospect, so the change LGTM.