This commit is part of a task to replace Paris with Doctrine in the
class ConfirmationEmailMailer. Specifically, it removes two calls to
Subscriber::setError() inside ConfirmationEmailMailer::sendConfirmationEmail().
setError() was used to define an error message that was used only in one
of the instances where sendConfirmationEmail() is called
(API::subscribeToLists()). setError() was replaced with code that throws
an exception when there is an error. Thus it was necessary to change all
the places where ConfirmationEmailMailer::sendConfirmationEmail() is
called to handle the exception.
In some cases, there are some oddities as sendConfirmationEmail() can
return false or throw an exception in case of an error and calling code
must account for both. I decided to settle with this approach as
refactoring the rest of this method to use exceptions instead of
returning false seemed outside of the scope of this task.
[MAILPOET-3815]
d39d09dd72