Fix diagram generation in native samm-cli build

Author: atextor

core/esmf-native-support/src/main/java/org/eclipse/esmf/nativefeatures/DiagramFeature.java

@@ -257,6 +257,8 @@ private void setupAwt() {
       Native.forClass( java.awt.GraphicsEnvironment.class )
             .registerMethodForJni( "getLocalGraphicsEnvironment" )
             .registerMethodForJni( "isHeadless" );
+      Native.forClass( "java.awt.GraphicsEnvironment$LocalGE" )
+            .registerClassForReflection();
       Native.forClass( java.awt.event.KeyEvent.class )
             .registerFieldsForJni( "isProxyActive" );
       Native.forClass( java.awt.geom.AffineTransform.class )

core/esmf-test-aspect-models/src/main/java/org/eclipse/esmf/test/InvalidTestAspect.java

@@ -18,6 +18,7 @@
 public enum InvalidTestAspect implements TestModel {
    ACTUALLY_JSON,
    ASPECT_WITH_INVALID_VERSION,
+   ASPECT_WITH_LANG_STRING_WITH_EMPTY_LANGUAGE_TAG,
    ASPECT_WITH_RECURSIVE_PROPERTY,
    INVALID_SYNTAX,
    INVALID_ENCODING,

core/esmf-test-aspect-models/src/main/resources/invalid/org.eclipse.esmf.test/1.0.0/AspectWithLangStringWithEmptyLanguageTag.ttl

@@ -0,0 +1,28 @@
+# Copyright (c) 2025 Robert Bosch Manufacturing Solutions GmbH
+#
+# See the AUTHORS file(s) distributed with this work for additional
+# information regarding authorship.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# SPDX-License-Identifier: MPL-2.0
+
+@prefix : <urn:samm:org.eclipse.esmf.test:1.0.0#> .
+@prefix samm: <urn:samm:org.eclipse.esmf.samm:meta-model:2.2.0#> .
+@prefix samm-c: <urn:samm:org.eclipse.esmf.samm:characteristic:2.2.0#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+
+:AspectWithLangStringWithEmptyLanguageTag a samm:Aspect ;
+   samm:preferredName "Test Aspect"@en ;
+   samm:description "This is a test description"@en ;
+   samm:properties ( :testProperty ) ;
+   samm:operations ( ) .
+
+:testProperty a samm:Property ;
+   samm:preferredName "Test Property"@en ;
+   samm:description "This is a test property."@en ;
+   samm:exampleValue "invalid without language tag"^^rdf:langString ;
+   samm:characteristic samm-c:MultiLanguageText .