Based on a suggestion during the review of the PR, it was decided that
it makes more sense for the code that was created as
SendingQueueEntity::toArray() tp be moved to
SendingQueuesResponseBuilder::build(). It is used only to build the
format that is send in the API response.
[MAILPOET-4368]
This was the easiest way to fix failing integration tests related to
updating some Sending methods to use Doctrine instead of Paris. Using
Paris in SendingQueue to update the database was creating a state where
Doctrine had stale data and this was causing the tests to fail.
[MAILPOET-4368]
