test: Add assert for non blank modelName

src/test/java/no/nibio/vips/model/septoriareferencehumiditymodel/SeptoriaReferenceHumidityModelTest.java

@@ -93,6 +93,7 @@ public class SeptoriaReferenceHumidityModelTest {
         SeptoriaReferenceHumidityModel instance = new SeptoriaReferenceHumidityModel();
         String result = instance.getModelName();
         assertNotNull(result);
+        assertTrue(!result.isBlank());
     }
 
     /**