There are two speeches. Zeb is watching the one from the Senate with Imperial commentary on Chopper, this is the same one as the one in Andor.
The second speech is the one where she calls the Rebels together and is only in the Rebels episode but is the one they talk about having her make at the end of Andor.
As the speech from the Senate in Rebels is framed with Imperial commentary it is either the end of her speech we didn’t hear as the power was cut or an Imperial edit put out to try take control of the narrative. Either way, it isn’t a live version of what was made in Andor.
It’s also possible it’s a direct retcon between the animation and live action in the same way Hera is suddenly 50cm taller or Mon has a different haircut but it’s still possible to just see it as different parts of the same event with only minor mental gymnastics.