Try using replace substring. Source is your string you want to remove newlines from. To is just blank, no string goes in there.
For From, hold Shift and press Enter. This will stay in the text field and create a newline. It will look tall, like in the attached image.
This may not work for all strings but between this solution and the \r and \n solution you should cover pretty much everything. It depends on where the string comes from, as different environments may handle new lines in unique ways.
Runtime DataTable : Import and export game data to and from CSV or Google Sheets while your game is running!
easyCSV : Read data from any CSV and put them in an easy-to-access string map!
iTween : Free, smooth, procedural object animation