Let \( A_{1}, A_{2}, A_{3}, \ldots, A_{8} \) be the vertices of a regular octagon that lie on a circle of radius \( 2 \). Let \( P \) be a point on the circle and let \( PA_{i} \) denote the distance between the points \( P \) and \( A_{i} \) for \( i=1,2,\ldots,8 \). If \( P \) varies over the circle, then the maximum value of the product \( PA_{1}\cdot PA_{2}\cdots PA_{8} \), is: