feat: add a sentence to mock a request with a fixture and a status code at the same time

Combine two existing sentences to get the following sentence :
I mock a request {} on url {string} named {string} with fixture {} and status code {int}

Search the repository for the two existing request-mocking sentences and their step definitions. Combine them into the exact sentence shown in the issue, then verify that the resulting step accepts both a fixture and a status code.

Written by the indexing model from the issue text.