how to publish user defined table type as an article in Transactional replication
UDTs are not articles that can be added to a publication directly. They are often used in stored procedures, so when you publish a stored procedure that depends on a UDT, the table type is scripted with the procedure itself.

In this case, it looks like the snapshot agent is failing while scripting the UDT. You could investigate the issue by changing the -OutputVerboseLevel switch to 2 and look for meaningful error messages in the output.

Another option is to remove the offending procedure from the publication and script it manually, along with its UDT.