If HPOS is disabled, or COT is no longer authoritative, then requests to access HPOS admin screens should result in redirects to the corresponding legacy order screen.

Closes #35074.

How to test the changes in this Pull Request:

1. To test, you will first need to setup HPOS—making the custom order tables authoritative and enabling sync (please refer to this PR if you need a primer on how do this). You will also need a number of test orders to play with: if you don't have any existing order data, consider using a tool like WC Smooth Generator for that.
2. Next, visit WooCommerce ‣ Settings ‣ Advanced ‣ Custom Data Stores and change the data store to the WordPress Posts Table.
3. Try accessing the HPOS order admin list table at /wp-admin/admin.php?page=wc-orders: you should be redirected to the equivalent order post screen at wp-admin/edit.php?post_type=shop_order.
4. Repeat, but use a paged URL such as wp-admin/edit.php?post_type=shop_order&paged=3: you should be redirected to /wp-admin/edit.php?paged=3&post_type=shop_order (assuming you have at least 3 pages of order data).
5. Now try accessing the order editor via the HPOS new order screen at /wp-admin/admin.php?page=wc-orders&action=new: you should be redirected to /wp-admin/post-new.php?post_type=shop_order (simulates manually creating a new order).
6. Try acessing the order editor for an existing order, using a URL like https://wordpress.lab/wp-admin/admin.php?page=wc-orders&action=edit&id=123: you should be redirected to /wp-admin/post.php?action=edit&post=123 (of course, change 123 to the ID of an actual existing order within your test site).

Now a more advanced test.

1. Return to WooCommerce ‣ Settings ‣ Advanced ‣ Custom Data Stores and change the data store to the WooCommerce Orders Tables.
2. Visit the order admin list table at /wc-admin/admin.php?page=wc-orders and select one or more orders, then perform a bulk action such as changing the order status to Completed.
   • You will also need to use your browser's developer tools for this test (if you are using Firefox, I recommend the Network tab with Persist Logs enabled), or some equivalent tool, to capture the initial URL that is created when you do this.
   • Typically, it will take the form /wp-admin/admin.php?page=wc-orders&_wpnonce=ABCDEF&_wp_http_referer=%2Fwp-admin%2Fadmin.php%3Fpage%3Dwc-orders&action=mark_completed&order%5B%5D=1&order%5B%5D=2&action2=mark_completed (but you may also see some extra query parameters in there).
3. Go back to WooCommerce ‣ Settings ‣ Advanced ‣ Custom Data Stores and change the data store to the WordPress Posts Table.
4. Now try "re-playing" the URL you captured earlier, but change both instances of mark_completed to mark_processing. An appropriate redirect should take place and the bulk action should be processed, in this case resulting in the two orders being set back to "Processing".

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you created a changelog file for each project being changed, ie pnpm --filter=<project> changelog add?

FOR PR REVIEWER ONLY:

• I have reviewed that everything is sanitized/escaped appropriately for any SQL or XSS injection possibilities. I made sure Linting is not ignored or disabled.