Fix possible mailing to non-existing EIC

submissions/templates/submissions/_submission_card_author_content.html

@@ -8,8 +8,10 @@
     <p class="card-text">Status: {{submission.get_status_display}}</p>
 
     {% if current_user and current_user.contributor == submission.submitted_by %}
-        <p>
-            <a href="{% url 'submissions:communication' arxiv_identifier_w_vn_nr=submission.arxiv_identifier_w_vn_nr comtype='AtoE' %}">Write to the Editor-in-charge</a>
+        <p class="card-text">
+            {% if submission.editor_in_charge %}
+                <a href="{% url 'submissions:communication' arxiv_identifier_w_vn_nr=submission.arxiv_identifier_w_vn_nr comtype='AtoE' %}">Write to the Editor-in-charge</a>
+            {% endif %}
             {% if submission.status == 'revision_requested' %}
             &middot; <a href="{% url 'submissions:prefill_using_identifier' %}?identifier={{submission.arxiv_identifier_wo_vn_nr}}">Resubmit this manuscript</a>
             {% endif %}