Update FastBroadcast extension to Serial dispatch (v3 backport)#556

ChrisRackauckas merged 1 commit intoSciML:v3-backportSciML/RecursiveArrayTools.jl:v3-backportfrom

ChrisRackauckas-Claude:fix-fb-v3-backportChrisRackauckas-Claude/RecursiveArrayTools.jl:fix-fb-v3-backportCopy head branch name to clipboard