[Metrics] Add recovered context to the Inventory Threshold rule

[Kerry350]

Summary

The alerting framework now supports context on the recovered group.

Please see this issue first: #126617

Implementation hints

• We need to set doesSetRecoveryContext to true on the rule type. The rule is registered here: https://github.com/elastic/kibana/blob/main/x-pack/plugins/infra/server/lib/alerting/inventory_metric_threshold/register_inventory_metric_threshold_rule_type.ts#L64

• Relevant action variables: https://github.com/elastic/kibana/blob/main/x-pack/plugins/infra/server/lib/alerting/inventory_metric_threshold/register_inventory_metric_threshold_rule_type.ts#L93

Inside the rule executor, when the executor has finished scheduling actions for active alerts, the following code should be added:

// Call done() to gain access to recovery utils
// If `doesSetRecoveryContext` is set to `false`, getRecoveredAlerts() returns an empty list
const { getRecoveredAlerts } = alertsFactory.done();

for (const alert of getRecoveredAlerts()) {
	const alertId = alert.getId();
	alert.setContext({
		CONTEXT HERE!
	})
}

(Taken from meta issue)

• Here is an example of where we set fired context: https://github.com/elastic/kibana/blob/main/x-pack/plugins/infra/server/lib/alerting/inventory_metric_threshold/inventory_metric_threshold_executor.ts#L85

• Some code already exists for recovered handling, but is disabled, e.g:

• https://github.com/elastic/kibana/blob/main/x-pack/plugins/infra/server/lib/alerting/inventory_metric_threshold/inventory_metric_threshold_executor.ts#L159

• https://github.com/elastic/kibana/blob/main/x-pack/plugins/infra/server/lib/alerting/inventory_metric_threshold/inventory_metric_threshold_executor.ts#L196

• https://github.com/elastic/kibana/blob/main/x-pack/plugins/infra/server/lib/alerting/inventory_metric_threshold/inventory_metric_threshold_executor.ts#L17

Acceptance Criteria

• All (or the ones that make sense) of our context variables should be available as part of the recovered group.

[elasticmachine]

Pinging @elastic/infra-monitoring-ui (Team:Infra Monitoring UI)

[smith]

Duplicate of #126279.