[ios]Further investigate iOS 18.2 WebView behavior

[hellohuanlin]

This is a follow-up for the original issue here

On iOS 18.2 the web view's gesture recognizer likely cached the old state of our FlutterDelayingGestureRecognizer (see PR description here).

The current workaround doesn't address a problem where a platform view receives the gesture even when it shouldn't have. (See discussion here)

Also this is potentially a bug on iOS, so we may wanna create a reproducible project in UIKit and file the radar with Apple.