It's worth noting that https://creativecommons.org/faq/#artificial-intelligence-and... itself takes the general stance that "as a general matter text and data mining in the United States is considered a fair use and does not require permission under copyright."
But as a practical matter, I wouldn't be surprised if some Wikipedia editors balk at their volunteer work being actively marketed and reformatted for ease of LLM training by the very platform that solicited their volunteer services, regardless of their works' legal status and Wikimedia's technical respect of that legal status.