conf.d load order changed in 3.1.0 release

Prior to updating to fish 3.1.0, I was able to predict the load order of files in my .config/fish/conf.d/ folder. I designed this folder with a ___env.fish file to set some global exported variables that could be shared among configuration files that would load later.

Now, after updating to fish 3.1.0, the __env.fish file loads last instead of first.