Backport: Remove duplicate hst-container-item when it's defined in the template of a component

When an hst-container-item is placed within the component template (instead of the default container template), the HTML element with class hst-container-item is not replaced correctly when the component settings are changed. This results in a duplicate hst-container-item element, whereby the first element isn't correctly redrawn. Therefore any changed parameters will not be reflected on that element (only at the newly created inner element).

Example output, after changes the component properties (and thereby reloading the component HTML):

<div class="hst-container-item with-old-properties" id="c9e8e3c6-410c-413b-9730-553cd41f4b3c" uuid="c9e8e3c6-410c-413b-9730-553cd41f4b3c" type="CONTAINER_ITEM_COMPONENT" xtype="HST.Item" url="/_cmsinternal/kpn/_hn:component-rendering%7Cr17_r1_r6_r1/administratief-backoffice" refns="r17_r1_r6_r1" hst-container-lastmodified="1377074826206" hst_internal_variant="hippo-default">
<div class="hst-container-item with-new-properties">
...
</div>
</div>