Forms containing multibyte characters cannot be exported to PDF correctly

Issue Summary

Forms containing multibyte characters such as Japanese cannot be exported to PDF correctly. Multibyte characters are replaced by ###.

Steps to Reproduce

1. Create a form and link it to a request type
2. Raise a request using the above form with multibyte characters such as Japanese
   
3. Export the submitted form to PDF by clicking ... > Download PDF / Download RIch PDF

Expected Results

A downloaded PDF file contains multibyte characters.

Actual Results

A downloaded PDF file doesn't contains multibyte characters, and they are replaced by ###.

Workaround

Use Download XLSX which contains multibyte characters correctly