add credit expired event (#19037)

Author: anmandan

specification/consumption/resource-manager/Microsoft.Consumption/stable/2021-10-01/consumption.json

@@ -5030,7 +5030,8 @@
             "PendingNewCredit",
             "PendingExpiredCredit",
             "UnKnown",
-            "NewCredit"
+            "NewCredit",
+            "CreditExpired"
           ],
           "x-ms-enum": {
             "name": "EventType",