Threshold rule less than or checking when count is 0

[kulbozz]

Is your feature request related to a problem? Please describe.
Problem statement: monitor for a condition with less than operator, supporting 0.

Describe the solution you'd like
I'm trying to implement a rule for monitoring when a rule hasn't has any alerts in X time period. Threshold rule only supports greater than and trying in ESQL counting also doesn't not count unless a value is present.

Describe alternatives you've considered
Here's an example in ESQL counting the number of building block alerts:

from .alerts-security.alerts
| where kibana.alert.building_block_type == "default"
| stats alert_count = count(*) by kibana.alert.rule.name
| where alert_count == 0

I want to know if a building block rule has 0 alerts in the last 1 week.