LP#1887852 Pending patron passwords aren't initially set to phone #

LP#1887852 Pending patron passwords aren't initially set to phone #

If a patron self registers with a phone # and the org unit
setting to use the phone for the password is true, when the
pending patron stage loads the password is initially random
instead of the last 4 digits of the phone #.

This branch sets the password to the last 4 digits of the phone
when the patron stage loads if the phone is set and the org
unit setting to use the phone # for the password is true.

To test:
1. Set org unit settings for allow patron self-registration and
   show day_phone on registration to true
2. Go to the OPAC and request a library card (include phone #)
3. Login to the staff client, Circulation->Pending Patrons and
   load the patron
4. Note the password is random
5. Load patch and repeat steps 3-4
6. Note the password is the last 4 digits of the phone #

Signed-off-by: Dan Briem <dbriem@wlsmail.org>
Signed-off-by: Mike Risher <mrisher@catalyte.io>
Signed-off-by: Jason Stephenson <jason@sigio.com>