chore: fix chat widget height issue (#40158)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **Style**
- Enhanced the display by updating the viewport height measurement,
allowing the content area to dynamically adjust based on the visible
screen space for a more responsive viewing experience.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

app/client/src/pages/AppViewer/index.tsx

@@ -60,7 +60,7 @@ const AppViewerBody = styled.section<{
   flex-direction: row;
   align-items: stretch;
   justify-content: flex-start;
-  height: calc(100vh - ${({ headerHeight }) => headerHeight}px);
+  height: calc(100dvh - ${({ headerHeight }) => headerHeight}px);
   --view-mode-header-height: ${({ headerHeight }) => headerHeight}px;
   contain: ${({ $contain }) => $contain};
 `;