This data has always been missing, the solution I used in "Workspace Usage" Workbook (look under [Regular Checks] --> Weekly --> Rules) - sorry its nested in lots of groups, if you go looking for the code"
1st query:
/subscriptions/{Subscription:id}/resourceGroups/{resourceGroup}/providers/Microsoft.OperationalInsights/workspaces/{Workspace:name}/providers/Microsoft.SecurityInsights/AlertRuleTemplates
then
/subscriptions/{Subscription:id}/resourceGroups/{resourceGroup}/providers/Microsoft.OperationalInsights/workspaces/{Workspace:name}/providers/Microsoft.SecurityInsights/AlertRules
then use a merge to join them - this does assume you are deploying from the Sentinel Github