Do you mean a Christian seder meal or an actual Jewish Passover meal?
A Christian seder meal is very similar to a Jewish one, but usually with a recognition that Jesus is the Messiah. They are more common than they used to be.
This is a grey area at the moment. Certainly, as a Catholic, you wouldn’t use the Passover meal at your friend’s house as a replacement for a Catholic Mass, but if you are comfortable in attending then you may do so. Again, it’s not a replacement for Mass, and if you feel comfortable then feel free to attend as a guest.
Personally, I would consider attending not as a worshipper and only as a guest.