fix xlsx boolean value

lib/submissions/generate_export_files.rb

@@ -150,6 +150,8 @@ module Submissions
 
               ActiveStorage::Blob.proxy_url(attachment.blob, expires_at:) if attachment
             end
+          elsif submitter_value == true || submitter_value == false
+            submitter_value.to_s
           else
             submitter_value
           end