Bug 33164: Do not prevent processing of all error messages

Bug 33164: Do not prevent processing of all error messages

This follow-up patch removes the use of $exit_required_p completely. The sysprefs BlockReturnOfLostItems and BlockReturnOfWithdrawnItems are handled in other scripts, and should not prevent the processing of all returns error messages when enabled.

Signed-off-by: Phil Ringnalda <phil@chetcolibrary.org>
Signed-off-by: Emily Lamancusa <emily.lamancusa@montgomerycountymd.gov>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 64460e4f4e01d8cb84a8037f444e5f7739a6bd40)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>