[FIX] gamification: update internal users goals

For performance reason, we avoided computing goals for the set of users
that didn't log in recently (See ec0c0f29).
However, users can stay logged in for a while without having a new "log
in event" (password asked), such that active internal users can keep
old values in their challenges when reports are sent, which is not good.

Until an improvement can be implemented in master, we drop this time
constraint for active internal users.

A test is added, checking the behavior of the method called by the cron.

Task-3226408

closes odoo/odoo#119271

Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>