[ Azure Logs ] Wrong mapping in the Activity Logs data set result in ignored fields and poor data set quality

Hello,

I was just checking the Data Set Quality feature in Kibana and saw that the worst offender and only data set with Poor quality was a native integration, more specifically the Azure Activity Logs.

Checking the reason for this I saw that almost all events have an `_ignored` field because of a wrong mapping.

The field `azure.activitylogs.level` is wrongly mapped as `long`, but the values in the documents are strings like _Informational_ or _Error_.

This field should be remapped as `keyword`.