internal/arms/API.SB.ConnectionString.json

{
  "type": "Microsoft.Web/connections",
  "apiVersion": "2018-07-01-preview",
  "name": "##NAME##",
  "location": "[parameters('logicAppLocation')]",
  "properties": {
      "api": {
          "id": "[subscriptionResourceId('Microsoft.Web/locations/managedApis', parameters('logicAppLocation'), 'servicebus')]"
      },
      "displayName": "##NAME##",
      "parameterValues": {
          "connectionString": "[listKeys(resourceId('##RESOURCEGROUPNAME##','Microsoft.ServiceBus/namespaces/authorizationRules', '##NAMESPACE##', '##KEYNAME##'), '2017-04-01').primaryConnectionString]"
      }
  }
}