Bug 30372: Fix value->attribute

Test plan:
- Activate patron self registration without email verification
- Create several patron attributes as visible and editable in the OPAC, make one mandatory
- Register as a new patron from the OPAC
- Fill in all required fields but the extended attribute
- Fill in at least one of the non-required extended attributes
- Submit
- Verify that the contents of the other extended attribute fields are still present.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 4616ddc8ab)
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>

opac/opac-memberentry.pl

@@ -671,7 +671,7 @@ sub GeneratePatronAttributesForm {
     # or taken from the patron itself
     if ( defined $entered_attributes ) {
         foreach my $attr (@$entered_attributes) {
-            push @{ $attr_values{ $attr->{code} } }, $attr->{value};
+            push @{ $attr_values{ $attr->{code} } }, $attr->{attribute};
         }
     }
     elsif ( defined $borrowernumber ) {