feat(admin_chat.html): add back button to admin chat

home/templates/chat/admin/admin_chat.html

@@ -68,8 +68,8 @@
 {% block content %}
   {% include "wagtailadmin/shared/header.html" with title="Chat" icon="mail" %}
   <div style="padding: 0 3em;">
-    <h1>{% trans "Admin Chat View" %}</h1>
-    <p>{% trans "Chat with" %} <strong>{{ chat_user.email }}</strong></p>
+    <a href="{% url 'user_chat' %}" class="button button-secondary">&larr; {% trans "Back" %}</a>
+    <h1>{% trans "Chat with" %} <em>{{ chat_user.email }}</em></h1>
 
     <ul class="admin-chat-messages">
       {% for message in chat_messages %}