This use case was not correctly managed as the function evaluating if the
value has changed compares datetime and date.
This triggered an issue if the widget `date` was set on the field `date_order`
on a purchase order for example ; it was not possible to create a record as
the datapoint was set `dirty`.
This rev. ensures that a `field_changed` is not triggered if the day is the same
on a date widget.
This rev. also adds support of `datetime` fields on date widget, which appears
to be a valid use case.
Fixes https://github.com/odoo/odoo/issues/20311
Martin Geubelle
2455350c40