added error bubble for duplicate GlobalAssetIds

src/AasxPackageLogic/DispEditHelperEntities.cs

@@ -65,6 +65,19 @@ public void DisplayOrEditAasEntityAssetInformation(
                     "found on its name plate. " +
                     "This  attribute  is  required  as  soon  as  the  AAS  is exchanged via partners in " +
                     "the life cycle of the asset.",
+                    severityLevel: HintCheck.Severity.High),
+                new HintCheck(
+                    () =>
+                    {
+                        int count = 0;
+                        foreach(var aas in env.AssetAdministrationShells)
+                        {
+                            if(aas.AssetInformation.GlobalAssetId == asset.GlobalAssetId)
+                                count++;
+                        }
+                        return (count>=2?true:false);
+                    },
+                    "It is not allowed to have duplicate GlobalAssetIds in the same file. This will break functionality and we strongly encoure to make the Id unique!",
                     severityLevel: HintCheck.Severity.High)
             });