fix #2484, Remove not-empty assert for Cookie.value

[laishere]

Connection with issue(s)

Resolve issue #2484

Testing and Review Notes

Run flutter_inappwebview/example/integration_test/cookie_manager/main.dart test.

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)

[mhlim8157]

any Updates?

[pichillilorenzo]

@all-contributors please add @laishere for code

[allcontributors]

@pichillilorenzo

I've put up a pull request to add @laishere! 🎉