Should custom sorting function has higher priority than `ivy--flx-sort`?

[cireu]

I'm testing a new fuzzy matching algorithm and I want to use it with ivy, but I found ivy--sort-flx will has highest priority in sorting functions when flx is installed and regex function is ivy--regex-fuzzy

https://github.com/abo-abo/swiper/blob/master/ivy.el#L3285

Maybe allow custom sorting function to override ivy--sort-flx is better.

[abo-abo]

Thanks, please test.