Ministry workers aren’t said to be able to Apparate at Hogwarts.
There’s nothing in either the books or movies that says that Ministry officials are able to Apparate onto Hogwarts grounds. It may be said in the new movie that the Ministry of Magic has the power to bypass protection from Apparition. However, in both the books and movies, we never see a Ministry official do it, even when they’re “opposing” Hogwarts.
The protection against Apparition might not extend to the bridge.
When Snape tries to escape from Hogwarts after carrying out his promise to Dumbledore that he’d kill him, Harry tried to stop Snape and Draco from reaching the gates, because once they get past the gates they’ll be able to Apparate.
“And now he saw the vast outline of Hagrid, illuminated by the light of the crescent moon revealed suddenly from behind clouds; the blond Death Eater was aiming curse after curse at the gamekeeper, but Hagrid’s immense strength, and the toughened skin he had inherited from his giantess mother, seemed to be protecting him; Snape and Malfoy, however, were still running; they would soon be beyond the gates, able to Disapparate –”
- Harry Potter and the Half-Blood Prince, Chapter 28 (Flight of the Prince)
It’s possible if the bridge is outside the main part of the Hogwarts grounds, that the protection doesn’t encompass the bridge, so they could Apparate onto the bridge and walk the rest of the way.
From just looking at the bridge (both me and two close friends looked at it), it seems like it could be an “entryway” bridge.
The virtual Hogwarts on Pottermore (available to anyone with an account has a bridge that matches the one in the trailer as the entrance.