The formula is incorrect in general because the right hand side might be defined while the left hand side is not.
For example if $f_n(z)=(-1)^n$, then $\Pi f_n(z)$ is not defined and so $|\Pi f_n(z)|$ isn't either; but obviously $\Pi |f_n(z)|$ is defined and its value is $1$.
But under auspicious circumstances I cannot exclude that something could be salvaged...
In contrast to what happens for series, there is no naïve notion of absolute convergence for infinite products of complex numbers: else the example above shows you would have the disastrous terminology that some absolutely convergent products are divergent!
The best substitute is that the convergence of $\Pi (1+|a_n|) $implies the convergence of $\Pi (1+a_n) $.
Beware that some books' tratment of infinite products is not quite satisfactory. If you want to take the safe way, I cannot recommend warmly enough
Remmert's Classical Topics in Complex Function Theory where the theme is handled right at the beginning of the book.