Can not get UserAgent value from RequestBody or the header of the request.

**Describe the bug**
When using a Request/Response Hook in Insomnia (2021.2.2), I am trying to get the UserAgent value from Insomnia as this is used as part of the authentication mechanism of my API. I am using an environment variable today to store the value, but every time the client updates, that value is wrong again and the API Authentication fails.

I should be able to grab the UserAgent value as either an inherit function of Insomnia, or I should be able to grab it as part of the requestHook that I am executing before the Request is submitted.

Is there a way to access it that I am not aware of?

Start with the Request/Response Hook and requestHook behavior described in the report, checking how request headers and the request body are exposed. No file or test is named; done would mean determining whether the UserAgent is accessible there or defining the supported way to obtain it.

Written by the indexing model from the issue text.