Delete unused code (#6026)

* Delete unused code

* Delete template

src/pretix/presale/templates/pretixpresale/forms/addon_choice_option.html

@@ -1,3 +0,0 @@
-{% load rich_text %}
-<label{% if widget.attrs.id %} for="{{ widget.attrs.id }}"{% endif %}>{% include "django/forms/widgets/input.html" %} {{ widget.label }}</label> {% if widget.attrs.description %}<span class="fa fa-info-circle toggle-variation-description" aria-hidden="true"></span>
-<div class="variation-description addon-variation-description">{{ widget.attrs.description|rich_text }}</div>{% endif %}