Add missing acts to VirtualizedList-test and migrate to async act (f…

…acebook#44997)

Summary:
Pull Request resolved: facebook#44997

Wrap `VirtualizedList-test` uses of `react-test-renderer` in `act` as appropriate, so as to pass under current React and mostly pass under React 19, with further fixes to come.

Changelog: [Internal]

Reviewed By: yungsters

Differential Revision: D58649295