How can I disable the Outlook app on my Mac from asking me if I want to upload it to OneDrive?

I have a client who uses the Outlook app on her iMac. She does not use OneDrive, the app was uninstalled from her iMac. Last week, she began getting a pop-up every time she went to upload a file regardless of its size asking if she wanted to upload it to OneDrive or attach a copy. She uses iCloud Drive and doesn't store anything in OneDrive. She does not want to see this pop-up. I have scoured the internet looking for how we can prevent this pop-up from appearing but every suggestion I have seen gives me directions that do not line up with the current version of Mac Outlook app or OWA.