[M365D] Mapping incidents as alerts

[jamiehynds]

In our latest M365D integration, the incidents pipeline is mapping event.kind:event but this results in External Alerts not populating and some detection rules not triggering. To address is, incidents should be mapped as alerts.

[piyush-elastic]

@jamiehynds, we are looking into it.

[elasticmachine]

Package m365_defender - 1.7.1 containing this change is available at https://epr.elastic.co/search?package=m365_defender