kafka-on-ubuntu: error loading the template

[kafka-on-ubuntu](https://github.com/Azure/azure-quickstart-templates/tree/master/kafka-on-ubuntu)

### Issue Details
When clicking "Deploy on Azure" on this page: https://github.com/Azure/azure-quickstart-templates/tree/master/kafka-on-ubuntu, I get forwarded to Azure, but there is an error message on the top of the page:
There was an error loading the template from URI 'https://raw.githubusercontent.com/Azure/azure-quickstart-templates/master/kafka-on-ubuntu/azuredeploy.json'. Ensure that the template is publicly accessible and does not have any comments.

### Repro steps (*if necessary, delete otherwise*)
1.Click "deploy on Azure" on https://github.com/Azure/azure-quickstart-templates/tree/master/kafka-on-ubuntu

Start with kafka-on-ubuntu/azuredeploy.json and reproduce the problem by clicking "Deploy on Azure" from the template page. Check why Azure cannot load the publicly accessible template, and consider the issue done when the deployment page loads the template without this error.

Written by the indexing model from the issue text.