Improve version grouping to handle duplicate models

Updated the groupByVersion method to use a LinkedHashMap for collecting models by their URN, ensuring duplicates are removed before grouping by version. This change improves the accuracy of version grouping when duplicate models are present.

Author: michelu89

aspect-model-editor-service/src/main/java/org/eclipse/esmf/ame/services/utils/ModelGroupingUtils.java

@@ -103,8 +103,21 @@ private Model createModel( final ModelElement element, final KnownVersion versio
    }
 
    private List<Version> groupByVersion( final List<Model> models ) {
-      return models.stream().collect( Collectors.groupingBy( model -> model.getAspectModelUrn().getVersion() ) ).entrySet().stream()
-            .sorted( Map.Entry.comparingByKey() ).map( entry -> new Version( entry.getKey(),
-                  entry.getValue().stream().sorted( Comparator.comparing( Model::getModel ) ).toList() ) ).toList();
+      return models.stream()
+            .collect( Collectors.toMap(
+                  Model::getAspectModelUrn,
+                  model -> model,
+                  ( existing, duplicate ) -> existing,
+                  LinkedHashMap::new
+            ) )
+            .values()
+            .stream()
+            .collect( Collectors.groupingBy( model -> model.getAspectModelUrn().getVersion() ) )
+            .entrySet()
+            .stream()
+            .sorted( Map.Entry.comparingByKey() )
+            .map( entry -> new Version( entry.getKey(),
+                  entry.getValue().stream().sorted( Comparator.comparing( Model::getModel ) ).toList() ) )
+            .toList();
    }
 }