So, I noticed on a half-elf character of mine (Link: https://www.dndbeyond.com/characters/98378324), on the Saving Throws portion of the sheet: "advantage against being charmed, and magic can’t put you to sleep." I think that the magical sleep part was supposed to go in the "Defenses" Tab instead of here (as immunity to magical sleep is not there).

That is generally intended in the dnd beyond design and always has been like that for me. Unless said otherwise.

The “Defenses” section is strictly in regards to Conditions. Since “sleeping” isn’t one of the official conditions, they didn’t put it there.