R1:d02beaf8161a

Make reloading workboards with "R" respect workboard ordering

Summary:
Depends on D20653. Ref T4900. Pass ordering details to the reload endpoint so it can give the client accurate ordering/header information in the response.

The removed comment mentions this, but here's why this is a difficult mess:

- In window A, view a board with "Group by: Owner" and no tasks owned by "Alice". Since "Alice" owns no tasks, this means the columns do not have an "Assigned to: Alice" header!
- In window B, edit task…