[IMP] bus: last notification id reset after restoring db

Before this PR, the last notification id known by the client
was not reset after restoring the database. This was an issue
since there can be a gap between the last notification  and the
one that has been restored with the database. In this scenario,
messages are not received after restoring the database since the
client subscribes to higher notification ids that the ones that are
created.

This PR fixes this issue by defaulting to 0 if the one the client
passed is higher.

closes odoo/odoo#103025

Signed-off-by: Sébastien Theys (seb) <seb@odoo.com>