This commit changes the length of the random string appended to segments
created from a template when a segment with the same name already
exists. Before the length was 12 and now it is 5. We don't need a very
long random string in this case, and the shorter the string the less
ugly it is.
[MAILPOET-5394]
This commits adds the sanitization right before the data is added to the
database (\MailPoet\Segments\SegmentsRepository::createOrUpdate()) and
removes the sanitization from
\MailPoet\Segments\DynamicSegments\SegmentSaveController::save() to
avoid sanitizing twice. save() calls createOrUpdate().
Before this commit, we were sanitizing the name and description of
dynamic segments but not regular segments.
[MAILPOET-5232]
