[The Might]

this act of bringing down its walls is similar to Luthien destroying Tol Sirion during the Quenta Silmarillion
it doesn't necessarily mean that she took place in the battle, but that is possible as well, I do not think she would stay at home and wait for Celeborn to come and tell her all the Orcs are dead and that she can go break down the walls
I personally think she did before the battle actually began