Bug 37339: Set messaging preferences from default on self registration

Bug 37339: Set messaging preferences from default on self registration

The change on bug 30318 prevented setting the default messaging preferences when none were passed.
Self registration relied on this for setting borrower preferences from the defaults.

This patch removes the call to handle_form_action and replaces it with a call to:
SetMessagingPreferencesFromDefault

To test:
 1 - Ensure self registration is enabled
 2 - Set default messaging preferences for the self registration category
 3 - Self register a patron from the OPAC, confirm defaults not set
 4 - Apply patch, restart all
 5 - Self register a patron
 6 - Confirm defaults have been set
 7 - Enable  PatronSelfRegistrationVerifyByEmail
 8 - Self register a patron on OPAC with an email
 9 - Find the email and grab the verification link (unless you have emails enabled)
     SELECT * FROM message_queue;
10 - Visit the link and confirm registration
11 - Confirm messaging defaults are set

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>