dev/sg-setup: add asdf-reshim step to regenerate shims

Created by: bobheadxi

I've seen two separate occasions (@kalanchan and @mucles ) where the asdf installations create a shim that point to the wrong version of asdf. I never encountered this, but for the rare cases where it shows up sg setup can recommend that we delete and regenerate the shims, which is what worked in both these scenarios.

Test plan

I deleted my asdf shims and re-ran sg setup -f which... seemed to work?