[MERGE] forward port branch saas-14 up to aaa2035b

addons/account/models/account_invoice.py

addons/account/tests/test_account_customer_invoice.py

addons/point_of_sale/static/src/js/models.js

addons/point_of_sale/static/src/js/screens.js

addons/pos_discount/static/src/js/discount.js

addons/web/static/src/js/framework/crash_manager.js

addons/web/static/src/less/navbar.less

addons/website_slides/controllers/main.py