Bug 30458: Include librarian (manager_id) in accountline when using "Payout amount...

Bug 30458: Include librarian (manager_id) in accountline when using "Payout amount" button

When using the "Payout amount" button, accountlines.manager_id is not
populated. This is not the case with the "Issue payout" buttons.

Test Plan:
1) Create a manual credit
2) Issue a payout using the "Payout amount" button
3) Inspect the payout accountline, note it has no manager_id
4) Apply this patch, restart all the things!
5) Repeat steps 1 and 2
6) Note the new payout accountline has a manager_id!

Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
JK: Fix commit title

Signed-off-by: Joonas Kylmälä <joonas.kylmala@iki.fi>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>