Reverting change in name pattern regex (Azure#23318)

Author: matthohn-msft

specification/communication/resource-manager/Microsoft.Communication/stable/2023-03-31/CommunicationServices.json

@@ -829,7 +829,7 @@
       "name": "communicationServiceName",
       "in": "path",
       "description": "The name of the CommunicationService resource.",
-      "pattern": "^[a-zA-Z0-9-]+$",
+      "pattern": "^[-\\w]+$",
       "minLength": 1,
       "maxLength": 63,
       "required": true,