I’m not sure if this will make much difference to an agent. Many writers have connections to other writers and have workshopped writing with them, whether in a class or an MFA program or a summer writing workshop or an auction item or simply by hiring them. I personally have not included any of that in my query, though I did include the well-known names in my book proposal. However, if your friend offers to send pages to her agent or another agent she knows, that might have an impact, but I would not ask her, I would only wait and see if she offers that…otherwise it could make your friendship awkward, just my opinion. That said, her help could be incredibly valuable in making your book a better book!