Avoid messages per entry from the handlers when they're not configured

[nahuelhds]

Avoid messages like

ERROR - Missing configuration values for publishing entry

This one is when you don't have Sendgrid configured.
Aside that this should be a warning and not an error (the user didn't do anything wrong here nor the process is not being able to continue).

The point is that if I didn't configure it, I don't want to be informed about this as it's a conscious choice. I assume something similar could be with the Twitter handler.

I say both notifies to the user that is it or it is not properly configured and so will be used in the process and then when the entries are parsed no other error/warning message is thrown