Dany doesn't come before Jon technically. He's the son of the oldest Targ son of the Mad King. The succession goes through Rhaegar's line. Doesn't matter because Jon wouldn't make a claim anyway.
That is not how succession works.
https://www.youtube.com/watch?v=RvWInrVgdLM @2:08
In the above lore vid on Robert's rebellion, it is mentioned that Aerys II skipped Rhaegar's line when it became known that he died. Plus, you guys seem to ignore the key bit of detail that while Jon was in the Night's Watch, Dany had already assumed the title of de facto Targ monarch. She's not the heir to Aery's crown, she has already taken it by virtue of there being no one else in front of her. People comparing this to the current British monarchy are also missing this point.
When Jon joins the Watch, and his uncle died, who is ahead of Dany to their family's crown? No one. She's not the crown princess, and she stops being an heir, but instead rightfully became Queen Daenerys. Jon years later dying and being resurrected, doesn't turn the clock on an already rightfully acquired title. As I've mentioned before, it's no different to Jorah not being able to just take the head of the Mormont family position from Lyanna, now that he's been pardoned by Robert. He lost his place in line, someone else ended up rightfully filling it, and now that he's pardoned, if anything he becomes her heir.