remove duplicate setter methods from child schema when parent schema contains same property

[XiaofeiCao]

code gen error in https://github.com/Azure/sdk-release-request/issues/2348

https://github.com/Azure/azure-rest-api-specs/blob/main/specification/botservice/resource-manager/Microsoft.BotService/preview/2021-05-01-preview/botservice.json#L2648-L2669

"allOf": [
    {
     "$ref": "#/definitions/WebChatSite"
    },
   {
     "$ref": "#/definitions/DirectLineSite"
   }
]

WebChatSiteand DirectLineSite contain same property siteName and code gen generates duplicate methods in child schema.