Avoid warning about unlikely argument

* container.getContainedElements() is of type List<IHierarchicElement>
* The (unchecked) cast of elementRef -> IHierarchicElement has already
  been present in the previous version of this method

Issue-Ref: 3539
Issue-Url: https://af3-developer.fortiss.org/issues/3539

Signed-off-by: Simon Barner <barner@fortiss.org>

org.fortiss.tooling.base/src/org/fortiss/tooling/base/library/.ratings

-ModelElementLibraryService.java ad618d79106b45f9b63856023a1df1ab65f2cec7 GREEN
+ModelElementLibraryService.java aae1cda83bd706a5798169daa4a64db5be0a0588 YELLOW

org.fortiss.tooling.base/src/org/fortiss/tooling/base/library/ModelElementLibraryService.java

@@ -141,7 +141,8 @@ public class ModelElementLibraryService implements ILibraryService {
 			final ILibraryElementReference elementRef) {
 		IHierarchicElement wrapped = (IHierarchicElement)elementRef.getLibraryElementShadow();
 		IHierarchicElement container = (IHierarchicElement)elementRef.eContainer();
-		container.getContainedElements().remove(elementRef);
+		IHierarchicElement elementRefHierarchicElement = (IHierarchicElement)elementRef;
+		container.getContainedElements().remove(elementRefHierarchicElement);
 
 		// preserve the ID of the reference
 		((IIdLabeled)wrapped).setId(((IIdLabeled)elementRef).getId());
@@ -151,7 +152,7 @@ public class ModelElementLibraryService implements ILibraryService {
 		wrappedConnectorsList.addAll(wrapped.getConnectors());
 		wrapped.getConnectors().clear();
 		EList<IConnector> elementRefConnectorsList = new BasicEList<IConnector>();
-		elementRefConnectorsList.addAll(((IHierarchicElement)elementRef).getConnectors());
+		elementRefConnectorsList.addAll(elementRefHierarchicElement.getConnectors());
 		for(IConnector elemRefConnector : elementRefConnectorsList) {
 			wrapped.getConnectors().add(elemRefConnector);
 			String elementRefConnectorName = ((INamedElement)elemRefConnector).getName();