tests: Add virtio net ctrl queue test for confidential VMs

Add test_virtio_net_ctrl_queue to the common_cvm integration
test module to verify that virtio net control queue functionality
works correctly in confidential guest environments.

The test creates an Ubuntu Jammy-based confidential VM using
GuestFactory and delegates to the existing
_test_virtio_net_ctrl_queue helper to validate MTU configuration
and ethtool offload settings.

Signed-off-by: Muminul Islam <muislam@microsoft.com>

cloud-hypervisor/tests/integration.rs

@@ -14993,4 +14993,12 @@ mod common_cvm {
             GuestFactory::new_confidential_guest_factory().create_guest(Box::new(disk_config));
         _test_pci_msi(&guest);
     }
+
+    #[test]
+    fn test_virtio_net_ctrl_queue() {
+        let disk_config = UbuntuDiskConfig::new(JAMMY_IMAGE_NAME.to_string());
+        let guest =
+            GuestFactory::new_confidential_guest_factory().create_guest(Box::new(disk_config));
+        _test_virtio_net_ctrl_queue(&guest);
+    }
 }