Remove oob template because support for it has been removed

aleksis/core/templates/oauth2_provider/authorized-oob.html

-{% extends "core/base.html" %}
-
-{% load i18n %}
-
-{% block content %}
-
-  {% if not error %}
-    <div class="container">
-      <div class="card green">
-        <div class="card-content white-text">
-          <div class="material-icons iconify small left" data-icon="mdi:check"></div>
-          <span class="card-title">{% blocktrans %}Success!{% endblocktrans %}</span>
-          <p>
-            {% trans "Please return to your application and enter this code:" %} {{ code }}
-          </p>
-        </div>
-      </div>
-    </div>
-  {% else %}
-    <div class="container">
-      <div class="card red">
-        <div class="card-content white-text">
-          <div class="material-icons iconify small left" data-icon="mdi:alert-octagon-outline"></div>
-          <span class="card-title">{% trans "Error" %}: {{ error.error }}</span>
-          <p>
-            {{ error.description }}
-          </p>
-          <p>
-            Please verify if the application is configured correctly or contact one of your site administrators:
-          </p>
-          {% include "core/partials/admins_list.html" %}
-        </div>
-      </div>
-    </div>
-  {% endif %}
-{% endblock %}