Bug 21915: Call reconcile_balance on manual invoice creation

Bug 21915: Call reconcile_balance on manual invoice creation

This patch makes the manual invoice creation step call
Koha::Account::reconcile_balance when the AccountAutoReconcile syspref
is set.

To test:
- Apply the patch
- Have some outstanding credit
- Create a manual invoice
=> SUCCESS: Same behaviour as always
- Set AccountAutoReconcile
- Create a manual invoice
=> SUCCESS: Reconcillation happened
- Sign off :-D

Sponsored-by: ByWater Solutions
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>