Fixes #4724 - Large attachments will blow up RAM and CPU usage on mysql.

app/models/application_model/checks_attribute_values_and_length.rb

@@ -52,6 +52,7 @@ def check_attribute_values_and_length
 
       # strip 4 bytes utf8 chars if needed (mysql/mariadb will complain it)
       next if self[name].blank?
+      next if column.type == :binary
 
       self[name] = self[name].utf8_to_3bytesutf8
     end