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

…44997)

Summary:
Pull Request resolved: #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: robhogan

Differential Revision: D58649295

fbshipit-source-id: 5e0fa791d581fbf004a2ca7eaa5c4b4d9a15ddfe