Delete a Node From a Search Tree

You are given the root of a binary search tree and an integer `key`. Delete the node whose value equals `key`, if it exists, while preserving the binary search tree property. Return the possibly new root of the tree. A binary search tree is defined as follows: for every node, all values in its left subtree are smaller than the node's value, and all values in its right subtree are larger than the node's value. Consider all cases: - The node does not exist. - The node is a leaf. - The node has exactly one child. - The node has two children. - The node to delete is the root. Example: ```text Input tree: 5 / \ 3 6 / \ \ 2 4 7 key = 3 One valid output tree: 5 / \ 4 6 / \ 2 7 ``` Implement a function that performs the deletion and returns the updated root.