flows: fix FlowNonApplicableException and EmptyFlowException leading to infinite spinners

passbook/core/templates/error/embedded.html

@@ -0,0 +1,25 @@
+{# Template used by bad_request_message within flows #}
+{% extends 'login/base.html' %}
+
+{% load static %}
+{% load i18n %}
+{% load passbook_utils %}
+
+{% block title %}
+{% trans card_title %}
+{% endblock %}
+
+{% block card_title %}
+{% trans card_title %}
+{% endblock %}
+
+{% block card %}
+<form method="POST" class="pf-c-form">
+    {% if message %}
+    <h3>{% trans message %}</h3>
+    {% endif %}
+    {% if 'back' in request.GET %}
+    <a href="{% back %}" class="btn btn-primary btn-block btn-lg">{% trans 'Back' %}</a>
+    {% endif %}
+</form>
+{% endblock %}