Fixed the is_in_section filter to return False when the resolver does not match at all in the Mia core application.

mia_core/templatetags/mia_core.py

@@ -206,6 +206,8 @@ def is_in_section(request, section_name):
         bool: True if the request is currently in this section, or False
             otherwise
     """
+    if request.resolver_match is None:
+        return False
     view_name = request.resolver_match.view_name
     return view_name == section_name\
            or view_name.startswith(section_name + ".")