revert change after PR review

Author: mattpollock

modules/openapi-generator/src/main/resources/r/api.mustache

@@ -153,11 +153,7 @@
 
       {{/vendorExtensions.x-streaming}}
       if (local_var_response$status_code >= 200 && local_var_response$status_code <= 299) {
-        if (is.raw(local_var_response$content)) {
-          return(local_var_response)
-        } else {
-          return(local_var_response$content)
-        }
+        return(local_var_response$content)
       } else if (local_var_response$status_code >= 300 && local_var_response$status_code <= 399) {
         return(local_var_response)
       } else if (local_var_response$status_code >= 400 && local_var_response$status_code <= 499) {