WHAT
Update one nightly pipeline to use custom SMTP config.

HOW
Add the parameters here: https://gitlab.cee.redhat.com/integreatly-qe/ci-cd/-/blob/master/jobs/Nightly/managed-api-install-addon-flow-z-candidate.groovy

Params to use:
from address: nightly@rhmw.io
host: smtp.sendgrid.net
password: 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
port:587
username: apikey

This is the followup of https://issues.redhat.com/browse/MGDAPI-3970

TESTS
N/A

DONE

• z-candidate pipeline uses custom SMTP config