Add Qwen2-7B to the list of zed.dev models (#15649)

Release Notes:

- N/A

---------

Co-authored-by: Nathan <nathan@zed.dev>

crates/collab/src/tests/test_server.rs

@@ -672,6 +672,8 @@ impl TestServer {
                 stripe_api_key: None,
                 stripe_price_id: None,
                 supermaven_admin_api_key: None,
+                qwen2_7b_api_key: None,
+                qwen2_7b_api_url: None,
             },
         })
     }