Add more E2E tests

[SteffenDE]

This issue tracks which areas could still benefit from (more) end to end tests.

Features

• [x] Streams
• [x] Uploads (could benefit from more test)
• [ ] Async operations
• [x] Live Navigation
• [x] Form recovery
• [x] Scroll position

Bindings

• [x] phx-feedback-for / phx-feedback-group
• [ ] debounce / throttle
• [ ] phx-viewport bindings
• [ ] Loading states
• ...

Feel free to adjust this as necessary.

[SteffenDE]

https://github.com/phoenixframework/phoenix_live_view/pull/3051 adds tests for live navigation and scroll restore

[SteffenDE]

https://github.com/phoenixframework/phoenix_live_view/pull/3061 adds tests for form recovery