fix(datatable): prevent stale closures when cellMemo is enabled

[Coderxrohan]

Problem

When cellMemo is enabled, memoized DataTable cells are not re-rendered for
existing rows when new rows are added, which can lead to stale closures in
body event handlers.

Solution

This change replaces index with rowIndex in cellMemoProps, ensuring
memoized cells are refreshed when row structure changes, while preserving
existing memoization behavior.

Notes

• Minimal and isolated change
• No public API changes
• Verified via reproduction and code inspection
• Full build:package was not run on Windows due to missing generated assets (components/libicons)

Fixes #8450 ( PrimeReact Datatable cellMemo causes stale closures in event handlers )