Before this commit, It was not possible to copy An employee which is already linked to User due `user_uniq` constraints.
Now we add `copy=False` on `user_id` field, so Employee will be copied without linked User.
closesodoo/odoo#49915
X-original-commit: 2a63df03859166414be338c6655ee8c4052666b7
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>
