It basically doesn't matter to what kind of vSwitch you connect the vCSA. However, the port group type may matter in case of issues with the vCSA. Make sure that you create an "Ephemeral" port group for the network to which the vCSA is connected, so that you can assign the vCSA to this port group from the ESXi host's embedded host client in case it's necessary (i.e. vCSA is down).
Thanks a lot for the input.