Allow jumping to desired wizard page through url query parameter

Problem/Motivation

The current implementation of the Webform Wizard does not support navigating directly to a specific wizard page using a URL query parameter. For example, accessing a URL such as:

https://example.com/test-form?page=3

does not take the user to the desired wizard page (page 3). Instead, the wizard enforces sequential navigation via "Previous" and "Next" buttons, and does not expose a mechanism for direct access to an arbitrary step via URL.

This limitation makes it difficult to implement user-friendly features like deep linking, bookmarking, or conditional navigation based on external input.
Steps to reproduce

Create a new Webform with 5 wizard pages.

Attempt to navigate directly to page 3 using a query parameter:

https://example.com/test-form?page=3

Observe that the wizard does not recognize the page query parameter and starts on the first page instead.

Let me know if you also want to include a proposed solution or patch suggestion.