Add conditional logic

src/registrar/templates/domain_users.html

@@ -31,7 +31,9 @@
       <tr>
         <th data-sortable scope="col" role="columnheader">Email</th>
         <th data-sortable scope="col" role="columnheader">Role</th>
+        {% if can_delete_users %}
           <th scope="col" role="columnheader"><span class="sr-only">Action</span></th>
+        {% endif %}
       </tr>
     </thead>
     <tbody>
@@ -41,6 +43,7 @@
           {{ permission.user.email }}
         </th>
         <td data-label="Role">{{ permission.role|title }}</td>
+        {% if can_delete_users %}
           <td class="shift-action-button">
             <a
               id="button-toggle-user-alert-{{ forloop.counter }}"
@@ -66,6 +69,7 @@
               </form>
             </div>
           </td>
+        {% endif %}
       </tr>
       {% endfor %}
     </tbody>

src/registrar/views/domain.py

@@ -630,6 +630,15 @@ class DomainUsersView(DomainBaseView):
         """The initial value for the form (which is a formset here)."""
         context = super().get_context_data(**kwargs)
 
+        domain_pk = None
+        can_delete_users = False
+        if self.kwargs is not None and "pk" in self.kwargs:
+            domain_pk = self.kwargs["pk"]
+            # Prevent the end user from deleting themselves as a manager if they are the
+            # only manager that exists on a domain.
+            can_delete_users = UserDomainRole.objects.filter(domain__id=domain_pk).count() > 1
+        context["can_delete_users"] = can_delete_users
+
         # Create HTML for the modal button
         modal_button = (
             '<button type="submit" '