ADD IBAN FIELD TO STRUCTS AND UPDATE PARSING LOGIC

- Added `iban` field to the `IbanEx.Iban` struct to hold the full IBAN value. - Updated the parsing logic to populate
the new field. - Adjusted BBAN rules and tests for France and Brazil to reflect updated structures. - Improved error
handling and format validation routines.

lib/iban_ex/country/so.ex

@@ -40,4 +40,3 @@ def to_string(
     |> Enum.join(joiner)
   end
 end
-