Make essentials banner component work with auto-generated content beans

The Essentials Banner component's default freemarker template has an explicit class check for the document type used. This is the specific line:

<#if document.class.name == 'org.example.beans.Banner'>

When the banner document is changed (by adding a field for instance), the bean class is also changed resulting in this statement evaluating to false. By changing the line to:

<#if hst.isBeanType(document, 'org.example.beans.Banner')>

the template would render as normal in both situations.

Alternatively, the entire type check can be replaced with <#if document??> which is what all other Essentials components appear to do.