Langfuse_v3_pipeline does not display the token count in the trace data

[camucamulemon7]

As I also mentioned in #556 , Langfuse_v3_pipeline is not retrieving the token count.
It might be due to a spec change on the OpenWebUI side, but it looks like usage is not being obtained correctly, so the token count is missing.

[alschenk]

check my fix here: #580
with this it works here.

[camucamulemon7]

It was resolved by the solution in #556 (comment)