Not even gonna.The DCEU wiki considers this canon.
It's from a comic called "Serving Up Justice"."Bravery isn't about lack of fear. It's about what you do when you're facing it. You asked for help when you needed it. That's super brave." ―Serena Williams to Mikayla Johnson[src] Serena Jameka Williams is a professional American tennis player who, at some point, was attacked by Retrobots...dcextendeduniverse.fandom.com
To be fair, she recognises the alternate Diana Prince as Wonder Woman, so her universe does seem to be the DCEU.
You can read it here.
I'll wait and see.I wonder if it's the same Firefly from the BVS comic?EXCLUSIVE: Brendan Fraser is set to join Leslie Grace in Warner Bros and DC Films’ Batgirl. Although not confirmed, sources believe Fraser would play the supervillain Firefly in the pic. Jacob Scip…deadline.com