Invalid html in testproject template

https://github.com/coderedcorp/wagtail-flexible-forms/blob/main/testproject/home/templates/home/stream_form_page.html#L51-L58:

```html
{% if step != steps|first %}

< Previous

{% endif %}

{% if steps|last == step %}Submit{% else %}Next >{% endif %}

```

The "Previous" and "Next" links could use some html entities :)