Resolve the responsible partner's email

Theo's renewal flow at Drumlin Advisory now has a list of contracts. Each row has a ResponsiblePartner column - a SharePoint Person column - and Naomi wants two emails for every contract: the partner's own address for the notification, and their manager's address as a fallback when nobody responds.

The Person column already carries the partner's email inline, so the first half is a one-token pull. The manager's email isn't on the row, so the second half needs an explicit lookup with Get manager (V2) - guarded so the flow doesn't fall over when a manager isn't set.