Microsoft.Billing | Update acceptanceMode Enum values to match with API response (#26230)

* Update acceptance mode enums values to match with API response

* adding one additiona default enum

Author: muazmian

specification/billing/resource-manager/Microsoft.Billing/stable/2020-05-01/billing.json

@@ -6333,9 +6333,13 @@
           "description": "The mode of acceptance for an agreement.",
           "readOnly": true,
           "enum": [
+            "Other",
             "ClickToAccept",
             "ESignEmbedded",
-            "ESignOffline"
+            "ESignOffline",
+            "PhysicalSign",
+            "Offline",
+            "Implicit"
           ],
           "x-ms-enum": {
             "name": "acceptanceMode",