This updates some of the segment listing messages to include the name of
the segment to avoid confusion, and allows for the possibility that
bulk actions will work for some segments but not all, in which case we
need to show both success and error messages.
MAILPOET-5395
Per WP security best practices, sanitization should be handled as early
as possible. So this commit move updates the calls to sanitize the
segment name and description to the part of the code where the user
input is first processed, instead of when the data is saved to the
database.
[MAILPOET-5232]
