Halo 4: Forward Unto Dawn (2012) Director - Stewart Hendler, Cinematography - Brett Pawlak โHonor, Valor, Allegiance, Excellence. From Earth, For Earth. Today. Tomorrow. Forever. Together We Rise. Together We Prevail. Forward Unto Dawn.โ
While Faith's VA isn't listed by name, but rather as "Additional Voices," there are three woman's voices in that category for "Beginnings": Enisha Brewster, Ashley Frost and Mary Elizabeth McGlynn. Now, the interesting thing about Mary Elizabeth McGlynn is that she's also the dialogue director for the show! However, she's also a voice actor among many other crew roles in many shows and video games.
I could find clips of Enisha Brewster on YouTube, so I don't think it's her. The only acting credit I could find for Ashley Frost was in this one episode of Tangled. Mary, though, has over 300 acting roles, including Coach Brunt in Carmen Sandiego, Zahara Hydris in Critical Role, and Governor Pryce in Star Wars: Rebels. "Beginnings" was not the only episode of Tangled she did voice work in, but she's always listed as "Additional Voices."
So though I'm not 100% sure, I think it's likely to be Mary, since she's the most experienced.
Bringing back a fancast that anon suggested that I LOVED. I assume sheโs one thatโs going to be casted as well very soon and itโd be pretty neat to have Sarah in Justice League as well.