Alerts with datemath are stuck with static values calculated at registration time

[ajhalani]

This is documented behavior so not a bug but an enhancement request. Currently the datemath in alerts is converted to static values at registration time. Hence these date-ranges don't work with alerts on datasets where date is a changing variable.

For e.g. functionality where user can get alerted on records (like scheduled events) matching his criteria in the next month in a rolling pattern without having to either re-ope index/re-start ES or re-register alert queries.

Thank you!

[clintongormley]

@ajhalani you're in luck - see #8534