refactor: For advances booked in Separate account, reconciliation date can be configured

[ruthra-kumar]

For advance payments that are booked in Separate Party account (https://docs.erpnext.com/docs/user/manual/en/advance-in-separate-party-account), reconciliation date can now be configured in Company master.

1. Reconciliation will happen either on Invoice Date or the Advance Payment date, whichever is the oldest. This is the default and expected behavior.
2. Reconciliation will always happen on the Advance Payment date.

continues: https://github.com/frappe/erpnext/pull/35609