ClientYamlTestClient can send too-long requests #65718
Description
Our YAML tests will randomly try and send a request body as a URL-encoded set of query parameters instead. There is a hard limit on how long an HTTP query string can be, and so the method ClientYamlTestClient#sendBodyAsSourceParam checks the size of the body and aborts if it is too long. However, this check does not take into account URL encoding, which means that a request body containing a large number of characters that need to be encoded can end up being longer than the HTTP query string limit.