ATTENTION PLEASE

This ticket had been merged previously and caused a regression that required a revert.
It is necessary to ensure that the job that failed in the initial merge does not fail in the second one.

The related Jira that made this one revertd is: https://jira.talendforge.org/browse/TDI-49755

Information

Currently, in a processor, if it has defined a @DiscoverSchema service, this service is call when the user click on 'Guess schema', and the schema is read on the standard output of the discover schema process.

If the service throws an exception, the no schema can be read and the studio display a very technical exception to the user.

We should be able to output a clear that will be displayed  to the final user. For instance, if, we sent in the standard output a know string like "// TCK - DISCOVERSCHEMA - ERROR", we should be able to write a json description of the error: 

// TCK - DISCOVERSCHEMA - ERROR
{
  "error": "The schema can't be inferred.",
  "action": "execute"
}