Add exception count to passive alerting API

We have some passive alerts that only see an alert message once, with the current default setup of the exception count none of these alerts will ever alert as the default is three. It would be good to be able to update this through the API as we have too many of these tests to make doing it manually feasible. Currently our rep is having to update it from the database once per week. It would be much more efficient if we could add this into the passive alerting API call.