gh does not handle conditional request 304 with empty body

[cderv]

res <- gh::gh("/users/hadley/repos", .limit = 2)
Etag <- attr(res, "response")$Etag
headers <- list("If-None-Match" = Etag)
res <- gh::gh("/users/hadley/repos", .limit = 2, .send_headers = headers)
#> Error in `httr2::resp_body_json()`:
#> ! Unexpected content type "NA".
#> • Expecting type "application/json" or suffix "json".

This is trying to use conditional request
https://docs.github.com/en/rest/using-the-rest-api/best-practices-for-using-the-rest-api?apiVersion=2022-11-28#use-conditional-requests-if-appropriate

gh is failing possibly because the body is empty which is expected with 304 return

While debugging the call

> resp
<httr2_response>
GET https://api.github.com/users/hadley/repos?per_page=2
Status: 304 Not Modified
Body: None

Possibly this is because gh call

> httr2::resp_body_json(response)
Error in httr2::resp_body_json(response) : 
  Unexpected content type "NA".
• Expecting type "application/json" or suffix "json".

gh/R/gh.R

Line 331 in 0d4b2b2

res <- httr2::resp_body_json(response)

this is error like this following

• check_content_type() should correctly error when response has no content_type but suffix is checked.  httr2#284

I believe gh should correctly handle the 304 Not Modified from Github.