Get Count Aggregate List View

GetCountAggregateListView.json

{
    "inputs": {
        "host": {
            "connectionName": "shared_sharepointonline",
            "operationId": "HttpRequest",
            "apiId": "/providers/Microsoft.PowerApps/apis/shared_sharepointonline"
        },
        "parameters": {
            "dataset": "https://contoso.sharepoint.com/sites/testsite",
            "parameters/method": "POST",
            "parameters/uri": "_api/web/lists/getbytitle('@{variables('ListName')}')/RenderListDataAsStream?View=@{variables('ViewID')}",
            "parameters/headers": {
                "Accept": "application/json;odata=nometadata",
                "Content-Type": "application/json;odata=nometadata"
            },
            "parameters/body": "{\n\"parameters\": {\n       \"RenderOptions\":5707271,\n       \"OverrideViewXml\":\"<View><Query><GroupBy Collapse=\\\"FALSE\\\"><FieldRef Name=\\\"Course\\\"/></GroupBy></Query></View>\",\n       \"AddRequiredFields\":true\n                        }\n}"
        },
        "authentication": {
            "type": "Raw",
            "value": "@json(decodeBase64(triggerOutputs().headers['X-MS-APIM-Tokens']))['$ConnectionKey']"
        }
    }
}