Log response body in PostJSONWithTimeout error case (#40509)

<!-- Add the related story/sub-task/bug number, like Resolves #123, or
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# Checklist for submitter


- [x] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
See [Changes
files](https://github.com/fleetdm/fleet/blob/main/docs/Contributing/guides/committing-changes.md#changes-files)
for more information.

## Testing

- [ ] QA'd all new/changed functionality manually

server/logging/webhook.go

@@ -45,7 +45,7 @@ func (w *webhookLogWriter) Write(ctx context.Context, logs []json.RawMessage) er
 		"url", server.MaskSecretURLParams(w.url),
 	)
 
-	if err := server.PostJSONWithTimeout(ctx, w.url, payload); err != nil {
+	if err := server.PostJSONWithTimeout(ctx, w.url, payload, w.logger.SlogLogger()); err != nil {
 		level.Error(w.logger).Log(
 			"msg", fmt.Sprintf("failed to send automation webhook to %s", server.MaskSecretURLParams(w.url)),
 			"err", server.MaskURLError(err).Error(),