Bugfix: message fields with type 'string' and format 'csv' are again stored as a parsed list of strings

[spacewolfXfr]

Fields of type 'string' and format 'csv' were already parsed correctly, but the new typing enforcement overruled the parsing (converted the list of strings back into a string).

Parsing of arrays and CSV have been removed from the Ivy raw string splitting, and instead is done based on the fields type and format information.