[Web]Remove the wrapper of webview to solve nestedscroll issue

[KevinnZou]

In this PR, Ben wrapped the Webview with a Framelayout to workaround rare crash. However, this led to the problem that the nested scroll does not work now. Since the AndroidViewHolder use view?.isNestedScrollingEnabled to determine whether the child view support nested scroll. It works well before this change because Webview supports nested scroll but failed now since FrameLayout does not. I opened an issue about this problem and Ben approved me to remove the Framelayout first to workaround this issue. Thus I finished it and submit this PR

Fixes #1652

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[bentrengrove]

Looking good! Thanks for this, just one minor thing to fix up and then it will be good to merge

[bentrengrove]

Thank you for the contribution!