[16.0][FIX] account_operating_unit: do not show inter-OU balance journals as invoice lines

[AaronHForgeFlow]

Fixes: https://github.com/OCA/operating-unit/issues/617

FW port of: https://github.com/OCA/operating-unit/pull/705

Converted boolean in the field display_type. Same as Odoo did in here: https://github.com/odoo/odoo/commit/d8d47f9ff8554f4b39487fd2f13c153c7d6f958d

Also added the operating unit column in the journal items list inside the journal entry form. That must be removed by mistake during the migration.

@ForgeFlow