[FIX] *: remove buggy calls to with_context

When .with_context() is called with a dictionary as 1st positional
argument, it will replace context (and not modify the referenced keys)
It may create bugs when losing the content of the context (e.g. remove
partner's language)

This is a partial backport of #36164 with the website part as
discussed.

closes odoo/odoo#36692

Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>