Tree: Ensure animation is stopped when uninstalling

Fixes #275

core/src/main/java/com/github/weisj/darklaf/ui/tree/DarkTreeExpansionAnimationListener.java

@@ -42,6 +42,15 @@ public class DarkTreeExpansionAnimationListener implements TreeExpansionListener
         tree.addTreeExpansionListener(this);
     }
 
+    public void install() {
+        this.tree.addTreeExpansionListener(this);
+    }
+
+    public void uninstall() {
+        animator.dispose();
+        this.tree.removeTreeExpansionListener(this);
+    }
+
     @Override
     public void treeExpanded(final TreeExpansionEvent event) {
         startAnimation(event.getPath());

core/src/main/java/com/github/weisj/darklaf/ui/tree/DarkTreeUI.java

@@ -168,7 +168,7 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
         selectionListener = createMouseSelectionListener();
         tree.addMouseListener(selectionListener);
         this.treeExpansionAnimationListener = createExpansionAnimationListener();
-        tree.addTreeExpansionListener(treeExpansionAnimationListener);
+        treeExpansionAnimationListener.install();
     }
 
     protected DarkTreeExpansionAnimationListener createExpansionAnimationListener() {
@@ -258,7 +258,7 @@ public class DarkTreeUI extends BasicTreeUI implements PropertyChangeListener, C
         tree.removeMouseListener(selectionListener);
         selectionListener = null;
         tree.removePropertyChangeListener(this);
-        tree.removeTreeExpansionListener(treeExpansionAnimationListener);
+        treeExpansionAnimationListener.uninstall();
         treeExpansionAnimationListener = null;
     }