Fix: Wait for a blank page to be loaded before closing the browser

[vladimir-beloded]

Connection with issue(s)

Resolve issue #1658

Testing and Review Notes

1. Open the website with the exit confirmation in the in-app browser on Android.
2. Try to close the in-app browser.
3. Observe the confirmation dialog.
4. Hit Stay on this page.
5. You should stay on the current page.
6. Try to close the in-app browser again.
7. Press Leave this page on the confirmation dialog.
8. The in-app browser should close.
9. Try to open this website again.
10. The page should be loaded again.

Screenshots or Videos

Before this fix:
https://github.com/pichillilorenzo/flutter_inappwebview/assets/98315622/a3acb3d6-5b16-4bb5-98e2-705c68ad87b2

After this fix:
https://github.com/pichillilorenzo/flutter_inappwebview/assets/98315622/115aa589-57d6-4417-8134-fc73440a66e8

To Do

• double check the original issue to confirm it is fully satisfied
• add testing notes and screenshots in PR description to help guide reviewers
• request the "UX" team perform a design review (if/when applicable)

[pichillilorenzo]

Unfortunately, this is not the intended behavior. The close function should just close the WebView and release all the resources, whatever the user is doing.

[vladimir-beloded]

@pichillilorenzo, then we, probably, should not show this popup at all since it causes an issue that breaks the in-app browser. Correct me if I'm wrong.

[vladimir-beloded]

@pichillilorenzo, any updates here?

[adminant]

I have the same issue, after closing InAppBrowser with confirmation active it hangs on next runs