fix: flashlist fixes (#3505)

## 🎯 Goal

This PR restores FlashList as a truly optional dependency by removing
the top-level runtime import path that made `@shopify/flash-list`
effectively mandatory at SDK startup. It also brings `FlashList` in line
with the existing `FlatList` overlay behavior by applying the same
`message-overlay` close correction when the list viewport height
changes, so context menu closing stays aligned during keyboard/composer
size changes.

## 🛠 Implementation details

<!-- Provide a description of the implementation -->

## 🎨 UI Changes

<!-- Add relevant screenshots -->

<details>
<summary>iOS</summary>


<table>
    <thead>
        <tr>
            <td>Before</td>
            <td>After</td>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>
                <!--<img src="" /> -->
            </td>
            <td>
                <!--<img src="" /> -->
            </td>
        </tr>
    </tbody>
</table>
</details>


<details>
<summary>Android</summary>

<table>
    <thead>
        <tr>
            <td>Before</td>
            <td>After</td>
        </tr>
    </thead>
    <tbody>
        <tr>
            <td>
                <!--<img src="" /> -->
            </td>
            <td>
                <!--<img src="" /> -->
            </td>
        </tr>
    </tbody>
</table>
</details>

## 🧪 Testing

<!-- Explain how this change can be tested (or why it can't be tested)
-->

## ☑️ Checklist

- [ ] I have signed the [Stream
CLA](https://docs.google.com/forms/d/e/1FAIpQLScFKsKkAJI7mhCr7K9rEIOpqIDThrWxuvxnwUq2XkHyG154vQ/viewform)
(required)
- [ ] PR targets the `develop` branch
- [ ] Documentation is updated
- [ ] New code is tested in main example apps, including all possible
scenarios
  - [ ] SampleApp iOS and Android
  - [ ] Expo iOS and Android

Author: isekovanic

package/src/components/MessageList/MessageFlashList.tsx

@@ -10,7 +10,7 @@ import {
 
 import Animated, { LinearTransition } from 'react-native-reanimated';
 
-import { FlashListProps, FlashListRef, useFlashListContext } from '@shopify/flash-list';
+import type { FlashListProps, FlashListRef } from '@shopify/flash-list';
 import type { Channel, Event, LocalMessage, MessageResponse } from 'stream-chat';
 
 import { useMessageList } from './hooks/useMessageList';
@@ -53,14 +53,20 @@ import { mergeThemes, useTheme } from '../../contexts/themeContext/ThemeContext'
 import { ThreadContextValue, useThreadContext } from '../../contexts/threadContext/ThreadContext';
 
 import { useStableCallback, useStateStore } from '../../hooks';
+import { bumpOverlayLayoutRevision } from '../../state-store';
 import { MessageInputHeightState } from '../../state-store/message-input-height-store';
 import { primitives } from '../../theme';
 import { MessageWrapper } from '../Message/MessageItemView/MessageWrapper';
 
+type FlashListContextApi = { getRef?: () => FlashListRef<LocalMessage> | null } | undefined;
+
 let FlashList;
+let useFlashListContext: () => FlashListContextApi = () => undefined;
 
 try {
-  FlashList = require('@shopify/flash-list').FlashList;
+  const flashListModule = require('@shopify/flash-list');
+  FlashList = flashListModule.FlashList;
+  useFlashListContext = flashListModule.useFlashListContext;
 } catch {
   FlashList = undefined;
 }
@@ -996,6 +1002,9 @@ const MessageFlashListWithContext = (props: MessageFlashListPropsWithContext) =>
       return;
     }
 
+    const closeCorrectionDeltaY = height - currentListHeightRef.current;
+    bumpOverlayLayoutRevision(closeCorrectionDeltaY);
+
     const changedBy = currentListHeightRef.current - height;
     flashListRef.current?.getNativeScrollRef()?.setNativeProps({
       contentOffset: { x: 0, y: flashListRef.current?.getAbsoluteLastScrollOffset() + changedBy },
@@ -1132,7 +1141,7 @@ const FlashListFooterTypingAdapter = ({
   const typingUsersLengthRef = useRef<number>(typingUsers.length);
 
   useEffect(() => {
-    const listApi = api?.getRef();
+    const listApi = api?.getRef?.();
 
     if (!enabled || !listApi) {
       return;