SkipJSONValidation in custom-api newRequest function

### Description

Sometimes I need to get HTML response from normal web page instead of api request, but I don't see any function that can skip json check.
In addition, I also want to add xpath function to parse html response.

Start by locating the custom-api newRequest function named in the issue and inspect how it validates responses. Clarify the intended behavior for skipping JSON validation and adding XPath parsing for HTML responses; done means both requested use cases are supported and covered by appropriate tests.

Written by the indexing model from the issue text.