fix(ios): retain WKHTTPCookieStore observer so cookie sync works

[Cybertron01Z]

Description

CAPBridgeViewController.webViewConfiguration(for:) added a CapacitorWKCookieObserver to the web view's httpCookieStore but did not keep any reference to it:

webViewConfiguration.websiteDataStore.httpCookieStore.add(CapacitorWKCookieObserver())

Per Apple's docs, WKHTTPCookieStore does not retain its observers:

The cookie store doesn't maintain a strong reference to the object you specify. You are responsible for removing your observer object before it becomes invalid.

So the observer was deallocated immediately after add(_:) returned, and cookiesDidChange(in:) never fired. The result: cookies set inside the WKWebView were never synced back to HTTPCookieStorage.

This PR holds a strong reference to the observer on the view controller, and also retains the store it was added to so the observer can be removed in deinit, as the docs require.

Change Type

• Fix
• Feature
• Refactor
• Breaking Change
• Documentation
• Other (CI, chores, etc.)

Rationale / Problems Fixed

The cookie observer was dead on arrival — cookiesDidChange never ran because the instance had no owner and was released right away. WKWebView → HTTPCookieStorage cookie syncing has therefore been silently broken.

The observer is now stored in an optional property assigned at the call site, so a subclass that overrides webViewConfiguration(for:) without calling the observer code creates no dangling instance. A weak reference to the exact WKHTTPCookieStore is kept so deinit can remove the observer per Apple's contract.

Tests or Reproductions

Tested manually:

• When the response sets a cookie, it is now successfully synced

Screenshots / Media

N/A

Platforms Affected

• Android
• iOS
• Web

Notes / Comments

The default websiteDataStore is the .default() singleton, so the store reference stays valid for the controller's lifetime; the weak reference avoids extending the store's lifetime or creating a retain cycle.