How to prevent "Look Up" functionality from showing link previews?
No definitive answer, but I do have a workaround for you.

Select the link including a whitespace before or after it, then use the look up function on the whitespace part of the selection.

Update: you can also look it up by selecting it and then right clicking a few pixels next to it (see picture). I find the quickest way to do this is right clicking the link to select it, than right clicking again right next to it to make the 'Look up' function appear.