Before this commit, the equality check performed by the datetime service
relied on a JSON-strigified version of the value on one end, and on an
array of ISO strings on the other end. This meant that the value was
never equal to itself and that the `onApply` callback would be called
even if the value remained unchanged.
This commit fixes that by ensuring that the compared values have the
same shape.
closesodoo/odoo#145929
Signed-off-by: Mathieu Duckerts-Antoine (dam) <dam@odoo.com>