Option to override Buyer SAN for select ACQ providers

Code:

https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/berick/lp1930753-acq-buyer-san-override

1. Would process_message_buyer in EDI.pm also need to be updated to reflect this alternate SAN so order responses/invoices are attached to the correct provider?

2. Even though "Buyer SAN" in the provider profile is technically correct, it's also potentially confusing language seeing as it's just two fields under "SAN." I think it would be helpful to either rename this "Alternate Library SAN"--as an example--or to add a tooltip that this should only be used for XYZ.

3. My totally non-technical inclination is that this field fits better under EDI accounts, since it's specifically only used when doing EDI ordering. Provider profiles are often accessible to a majority of Acq users, and EDI accounts might not always be (see bug 1916642). A user entering something in this field could potentially throw off their EDI orders because the vendor would be expecting the SAN from their mailing_address. That SAN is protected from unauthorized editing because getting into org unit settings requires a higher level of permissions.

Hi Bill, we applied this to a copy of our production data to test. When I put a pretend SAN in the new buyer_san field on the provider and run the test_edi script I'm not seeing the pretend SAN. Do I need to do anything after I add the new SAN?

Hi Tiffany, that's pretty much it. If there is a buyer_san on the PO provider, it should override the SAN on the org unit address.

Here's how I double-checked (change --po-id value to suit):

cd Open-ILS/src/support-scripts/test-scripts
./edi_writer.pl --po-id 43

---
UNA:+.? '
UNB+UNOB:3+VALUEHERE...
...

Works for me! Pushed to main.