Fix RHS scroll so AI plugin generation won't scroll off bottom (#27871)

* Fix RHS scroll so AI plugin generation won't scroll off bottom

* Fix scroll without breaking virtual list.

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Co-authored-by: Mattermost Build <build@mattermost.com>

webapp/channels/src/components/threading/virtualized_thread_viewer/virtualized_thread_viewer.tsx

@@ -451,6 +451,7 @@ class ThreadViewerVirtualized extends PureComponent<Props, State> {
                                     style={virtListStyles}
                                     width={width}
                                     className={'post-list__dynamic--RHS'}
+                                    correctScrollToBottom={true}
                                 >
                                     {this.renderRow}
                                 </DynamicSizeList>