To answer your immediate question, yes, it is possible to sneak-attack a dragon; as far as the mechanics of sneak attacks and detection go, dragons are much like any other enemy.
There's plenty of evidence that sneak attacks, in general, work against dragons, including this question with video evidence. I can also confirm that dragons that lose track of you will stop looking and allow you to return to "undetected" state after a while, so Shadow Warrior will work in theory.
However, I have not tried the specific combination you mentioned, so I'm not positive how effective it will be. Dragons appear to be very good at sensing enemies behind them when they are looking. Shadow Warrior works best against enemies that you are not very close to or that you're hidden from: it makes them lose track of where you are even if they used to know, but if they can still see you, it isn't nearly as effective. You will probably have to get the timing very precise to be effective.