[FIX] l10n_it_account: do not fail conversion on empty field

We don't want XML generation to fail if a field is empty (i.e. False)
Once it's time to validate the XML, the system will produce a more
meaningful and human-readable error.

Author: aleuffre

l10n_it_account/tools/account_tools.py

@@ -14,6 +14,8 @@
 
 
 def encode_for_export(string_to_encode, max_chars, encoding="latin"):
+    if not string_to_encode:
+        return ""
     return (
         reg_whitespace.sub(" ", string_to_encode)
         .encode(encoding, errors="replace")