replaceChild in BinaryTreeNode, the replacementNode's parent is incorrect

const leftNode = new BinaryTreeNode(1);
const rightNode = new BinaryTreeNode(3);
const rootNode = new BinaryTreeNode(2);
rootNode
  .setLeft(leftNode)
  .setRight(rightNode);
expect(rootNode.traverseInOrder()).toEqual([1, 2, 3]);

const replacementNode = new BinaryTreeNode(5);
rightNode.setRight(replacementNode);
expect(rootNode.traverseInOrder()).toEqual([1, 2, 3, 5]);

expect(rootNode.replaceChild(rootNode.right, rootNode.right.right)).toBe(true);

expect(rootNode.right.parent.value).toBe(2); // Expected: 2, but Received: 3

It's better to set replacementNode's parent to this.left/this.right in replaceChild method of BinaryTreeNode

Start at BinaryTreeNode.replaceChild and reproduce the case with the left, right, and replacement nodes shown in the issue. Verify the parent value after replacement and add or update the relevant BinaryTreeNode test so the replacement node is attached to the correct parent.