Ads setup screen becomes unusable if the WooCommerce redirect modal is dismissed

## Bug Description

On the Ads setup screen, a WooCommerce store with Google for WooCommerce active and an Ads account already linked via that extension is shown a modal asking whether to create another Ads account. That modal is intended to require an explicit choice — the code passes no close handler for this state — but it can still be dismissed with the Esc key or by clicking the overlay.

Once dismissed that way, it cannot be reopened: clicking "Start setup" again does nothing at all, with no error or feedback, and the Ads setup screen stays unusable until the page is reloaded. Pressing Esc on a modal is a common reflex, so a publisher can reach a dead end with no indication of what happened or how to recover.

Only this state is affected. In the other WooCommerce states, and from the dashboard setup CTA banner, dismissing and reopening works correctly.

## Steps to reproduce

- On a site with Site Kit connected and the Ads module **not** yet connected, install and activate both **WooCommerce** and **Google for WooCommerce**.
- Add a `gla_ads_id` option with any non-empty value — this is what Site Kit reads to detect an Ads account linked via the extension (`wp option update gla_ads_id 1234567890`, or add the row directly in the options table).
- Go to **Site Kit > Settings > Connect more services > Ads** and click **Start setup**.
- Confirm the modal is in the ads-connected state: it should be titled *"Are you sure you want to create another Ads account for this site?"* with the CTAs **Create another account** and **View current Ads account**.
- Press **Esc**, or click the grey overlay outside the dialog. The modal closes.
- Click **Start setup** again. Nothing happens — the modal does not reopen, no error is shown, and repeated clicks have no effect.
- Reload the page and click **Start setup**. The modal appears again, confirming the state is only recoverable by reloading.

## Screenshots

https://github.com/user-attachments/assets/eb30967d-6d38-4745-affe-08ef6e0f456f

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## Acceptance criteria

*

## Implementation Brief

* [ ]

### Test Coverage

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## QA Brief

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## Changelog entry

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Start from the Ads setup screen's Start setup action and the modal state for a WooCommerce-linked Ads account. Reproduce the Esc and overlay-dismissal paths, then verify that dismissing the modal no longer leaves setup unusable and that the modal can be opened again without reloading. Confirm the other WooCommerce states and dashboard setup CTA still behave correctly.

Written by the indexing model from the issue text.