fix: charset for telechat_agenda_content_view (#8967)

* fix: charset for telechat_agenda_content_view

* refactor: remove explicit encoding

HttpResponse knows how to read content_type and complies
with the specified encoding.

Author: jennifer-richards

ietf/iesg/tests.py

@@ -759,7 +759,7 @@ def test_telechat_agenda_content_view(self):
                 urlreverse("ietf.iesg.views.telechat_agenda_content_view", kwargs={"section": section})
             )
             self.assertContains(r, content, status_code=200)
-            self.assertEqual(r.get("Content-Type", None), "text/plain")
+            self.assertEqual(r.get("Content-Type", None), "text/plain; charset=utf-8")
 
     def test_telechat_agenda_content_view_permissions(self):
         for section in TelechatAgendaSectionName.objects.filter(used=True).values_list("slug", flat=True):

ietf/iesg/views.py

@@ -610,4 +610,4 @@ def telechat_agenda_content_manage(request):
 @role_required("Secretariat", "IAB Chair", "Area Director")
 def telechat_agenda_content_view(request, section):
     content = get_object_or_404(TelechatAgendaContent, section__slug=section, section__used=True)
-    return HttpResponse(content=content.text, content_type="text/plain")
+    return HttpResponse(content=content.text, content_type="text/plain; charset=utf-8")