Okay, I’ll assume that we’re stacking the bricks one on top of another, each brick being 8mm tall.
The semi-major axis of the Moon is (taking Wikipedia’s number as truth) 384,399 km, or 384,399,000m, and each brick is 8mm, or 0.008m.
So dividing one by the other, you get roughly 48.05 million bricks.
This is roughly the average number of bricks required, as the orbit of the Moon is actually an ellipse, meaning that it’s closer to us some times and further away from us other times.