fix bloc language when about has no language

app/models/communication/block.rb

@@ -99,7 +99,7 @@ class Communication::Block < ApplicationRecord
 
   def language
     return @language if defined?(@language)
-    @language ||= about.respond_to?(:language) ? about.language : nil
+    @language ||= about.respond_to?(:language) ? about.language : about.university.default_language
   end
 
   def duplicate