fix: Correctly generate primary keys

The generator was failing to identify primary key columns, resulting in generated beans without them. This has been fixed by updating the code to use the `getColumnsRef()` method, which correctly retrieves the column names for the primary key.

src/main/java/com/sdk/generators/actionmodels/GeneratorServices.java

@@ -129,7 +129,7 @@ public class GeneratorServices {
 
         dasKeys.forEach(key -> {
             if (key.isPrimary()) {
-                DasUtil.getColumns(key).forEach(column -> primaryKeys.add(column.getName().toUpperCase()));
+                key.getColumnsRef().names().forEach(column -> primaryKeys.add(column.toUpperCase()));
             }
         });