Add missing alert detais fields (Azure#16778)

Author: recalaz

specification/cost-management/resource-manager/Microsoft.CostManagement/stable/2021-10-01/costmanagement.json

@@ -2006,6 +2006,31 @@
             "overridingAlert": {
               "description": "overriding alert",
               "type": "string"
+            },
+            "departmentName": {
+              "description": "department name",
+              "type": "string"
+            },
+            "companyName": {
+              "description": "company name",
+              "type": "string"
+            },
+            "enrollmentNumber": {
+              "description": "enrollment number",
+              "type": "string"
+            },
+            "enrollmentStartDate": {
+              "description": "datetime of enrollmentStartDate",
+              "type": "string"
+            },
+            "enrollmentEndDate": {
+              "description": "datetime of enrollmentEndDate",
+              "type": "string"
+            },
+            "invoicingThreshold": {
+              "description": "invoicing threshold",
+              "type": "number",
+              "format": "decimal"
             }
           }
         },