Fix `process.ext` set with `withName` overrides all processes

[jorgeaguileraseqera]

We maintain in profileStack a list of sections visited but we were checking if the property requested was only into the scope of the current stack instead to check if present in the last profile

Another issue was we were checking if the var is present with if( current.scope[name] ) but this expression creates the variable if not present, so I've changed for containsKey

Lastly a little refactor removing the if-else-if chain for independents if who check if previous didn't find a valid result to return

closes #2422

[pditommaso]

The guru of ConfigSlurper! 😄

[pditommaso]

Can you give please have a look at the conflict?

[jorgeaguileraseqera]

done

after some errors in the pipeline due GitHub cache issue at the end, the pipeline ends ok

[pditommaso]

Unknown status. Closing it

[bentsherman]

This PR needs to be cleaned up but I believe it can be salvaged. Reopening