Clarify connecting account is a prerequisite for manual updates

When we looked at the “Connect with your UpdraftPlus.Com account” section on the Premium/Extensions settings page it isn’t immediately clear that connecting is a requirement for manual updates through the WordPress updates process. It sort of hints at it with the checkbox related to automating updates, but it doesn’t specify manual updates relay on the connection as well. It would be helpful to add a note to that effect in this section.

Thanks