fix(android): support NestedScrollView in ClippingScrollViewDecoratorView (#1527)

## Problem

With React Native's `useNestedScrollViewAndroid` feature flag (RN 0.85+,
facebook/react-native#55239), `ScrollView` renders as
`ReactNestedScrollView`, which extends
`androidx.core.widget.NestedScrollView` (a `FrameLayout`) — not
`android.widget.ScrollView`.

`ClippingScrollViewDecoratorView.findScrollView` only matches `view is
ScrollView`, so it returns null, `decorateScrollView()` silently no-ops,
and `contentInsetBottom`/`contentInsetTop` are dropped entirely. In a
`KeyboardChatScrollView` this means: list content hides behind the
composer, and `blankSpace`/`extraContentPadding` have no effect on
Android.

## Fix

Match `NestedScrollView` as well, and pass the found view around as
`ViewGroup`. Every member used by the decorator and the padding-scroll
workaround (`clipToPadding`, `getChildAt`, `setPadding`, `scrollBy`,
`scrollY`, `canScrollVertically`, `getLocationOnScreen`) lives on
`ViewGroup`/`View`, and `NestedScrollView` extends its scroll range via
bottom padding + `clipToPadding = false` exactly like `ScrollView`.

`ReactNestedScrollView` itself is package-private, hence matching on the
public androidx base class.

## Testing

Verified in a chat app (RN 0.85.3, new arch,
`useNestedScrollViewAndroid` enabled) via patch-package: composer inset,
keyboard padding, and `blankSpace` all apply again; behavior with the
flag disabled (plain `ScrollView`) is unchanged.

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