Fix nil pointer panic when exec some gitea cli command (#28791) (#28795)

Backport #28791 by @yp05327

panic:

![image](https://github.com/go-gitea/gitea/assets/18380374/7fcde2ad-1d42-4b60-b120-3b60a8926e8e)

After:

![image](https://github.com/go-gitea/gitea/assets/18380374/49d9f0ca-e590-4a35-8ca2-1317d1b7c939)

Co-authored-by: yp05327 <576951401@qq.com>

modules/private/actions.go

@@ -22,5 +22,8 @@ func GenerateActionsRunnerToken(ctx context.Context, scope string) (string, Resp
  })
 
  resp, extra := requestJSONResp(req, &responseText{})
+ if resp == nil {
+ return "", extra
+ }
  return resp.Text, extra
 }

modules/private/key.go

@@ -27,5 +27,8 @@ func AuthorizedPublicKeyByContent(ctx context.Context, content string) (string,
  req := newInternalRequest(ctx, reqURL, "POST")
  req.Param("content", content)
  resp, extra := requestJSONResp(req, &responseText{})
+ if resp == nil {
+ return "", extra
+ }
  return resp.Text, extra
 }

modules/private/mail.go

@@ -30,5 +30,8 @@ func SendEmail(ctx context.Context, subject, message string, to []string) (strin
  })
 
  resp, extra := requestJSONResp(req, &responseText{})
+ if resp == nil {
+ return "", extra
+ }
  return resp.Text, extra
 }