Bug 40850: (follow-up) Use add_or_update_attributes in copyright clearance methods

This patch simplifies the set_copyright_clearance_confirmed() method
to use the new add_or_update_attributes() method instead of custom
update/create logic.

Benefits:
- Reduces code complexity from 20+ lines to 6 lines
- Eliminates duplicate update/create logic
- Uses the new standardized method for attribute management
- Maintains all existing functionality and test coverage

Test plan:
1. Apply patch
2. Run:
   $ ktd --shell
  k$ prove t/db_dependent/Koha/ILL/Request.t
=> SUCCESS: Tests pass! Copyright clearance methods work with new implementation
3. Test copyright clearance workflow still works in ILL module
4. Sign off :-D

Signed-off-by: Martin Renvoize <martin.renvoize@openfifth.co.uk>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>

Koha/ILL/Request.pm

@@ -1319,25 +1319,9 @@ sub set_copyright_clearance_confirmed {
     # Normalize to boolean: 0 or 1
     my $value = $confirmed ? 1 : 0;
 
-    # Check if attribute already exists
-    my $existing_attr = $self->extended_attributes->find( { type => 'copyrightclearance_confirmed' } );
+    $self->add_or_update_attributes( { copyrightclearance_confirmed => $value } );
 
-    if ($existing_attr) {
-
-        # Update existing attribute
-        $existing_attr->value($value)->store;
-    } else {
-
-        # Create new attribute
-        $self->extended_attributes(
-            [
-                {
-                    type  => 'copyrightclearance_confirmed',
-                    value => $value,
-                }
-            ]
-        );
-    }
+    return $self;
 }
 
 =head3 add_or_update_attributes