tidy: deps: Hoist a complex multi-line if condition into a let
tidy: deps: Hoist a complex multi-line if condition into a let

This makes the code more readable, and eliminates a clippy warning.

aidancully/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,graydon/rust,graydon/rust,GBGamer/rust,graydon/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,graydon/rust,GBGamer/rust,aidancully/rust,graydon/rust