fix: closed review request "by (System)" (ietf-tools#4255)

Only display the user in the "Requested" column if it's a real human
(i.e., not "System").

Fix ietf-tools#3687

Author: Justin Iurman

ietf/templates/group/review_requests.html

@@ -166,7 +166,10 @@ <h2 class="mt-5" id="closed-review-requests">Closed review requests and assignme
                                 {{ r.type }}
                             </td>
                             <td>
-                                {{ r.time|date:"Y-m-d" }} by {% person_link r.requested_by %}
+                                {{ r.time|date:"Y-m-d" }}
+                                {% if r.requested_by.id != 1 %}
+                                    by {% person_link r.requested_by %}
+                                {% endif %}
                             </td>
                             <td>
                                 {{ r.deadline|date:"Y-m-d" }}