Provided that the author of the message you're replying to is indeed a member of the Animalia kingdom, they are all those creatures together (at the minimum), so yes, they have seen real light directly.

Of course, computers can be fitted with optical sensors, but our cognitive equipment has been carved over millions of years by these kind of interactions, so our familiarity with the phenomenon of light goes way deeper than that, shaping the very structure of our thought. Large language models can only mimic that, but they will only ever have a second-hand understanding of these things.

This is a different issue than the question of whether AI's are conscious or not.