Opening credits are a thing of the past on most TV shows nowadays. On US network broadcasting it cuts into the ever-expanding commercial time. The main reason Game of Thrones had one is it was the best place to stash the on-screen version of the books’ endpaper maps.
Even online-based shows like Star Trek Discovery just have a ten-second title card. I wouldn’t expect much more than that in The Mandalorian.
Actually a lot of shows still have title sequences these days. Certainly not the norm, but Game of Thrones is far from being the only one.
That said, it’s an interesting question what they’ll do regardless. Even if they only do a brief title card, will they have lower third credits that play throughout the opening few minutes (which is usually what happens in that case)? Or will they try to stick more to the Star Wars style and leave all the credits for the end? My guess would be the latter. But this being the first Star Wars live action show, it’s somewhat uncharted waters. We’ve only seen two examples of live action spin-offs before, both films. Makes me wonder about stylistic quirks - will there be wipes? will there be location titles? will each episode will begin with the GFFA card like the movies (or not, like the animated shows)?