feat(29): adjust certificate filename

The helper method 'pdf_file_name' was populating 'certificate.pdf.pdf'
3 jobs for feat/29-certificate-filename-adjustment in 49 minutes and 26 seconds (queued for 27 seconds)
Status Job ID Name Coverage
  Test
passed #159973
system

00:40:21

passed #159828
test

00:09:05

failed #159829
system

00:35:17