[FIX] mail: keep activity notification counter on today's meetings

Before this commit, when a user had some meetings planned today
and open the systray activity menu, the counter would disappear.

This was caused by a weak computation of the counter that relies
on activity having always a total counter. This was not the case
for activity that are today's meetings: Counter would be computed
as `NaN`, and since `NaN` is falsy, it won't display the counter.

Today's meetings have no reason to have a counter, so this commit
fixes the issue by letting those activities not change the
computation of the counter.

closes odoo/odoo#30695

0 files changed, 0 insertions, 0 deletions