refactor slices functions, with new slices functionality

[mtsitrin]

example:

this could all be shortened by a generic dedupe function, and https://pkg.go.dev/slices#ContainsFunc or https://pkg.go.dev/slices#IndexFunc

psuedo:

if len(permissioned) != len(deduped(permissioned)) {
..}
if i := slices.indexFunc(permissioned, func(x){
_, err := sdk.AccAddressFromBech32(x)
return err!=nil
}
}) {..}

something like that

Originally posted by @danwt in #712 (comment)