[management] Streamline domain validation (#5211)

management/server/util/util.go

@@ -1,9 +1,5 @@
 package util
 
-import "regexp"
-
-var domainRegex = regexp.MustCompile(`^(\*\.)?([a-zA-Z0-9-]+\.)+[a-zA-Z]{2,}$`)
-
 // Difference returns the elements in `a` that aren't in `b`.
 func Difference(a, b []string) []string {
 	mb := make(map[string]struct{}, len(b))
@@ -55,9 +51,3 @@ func contains[T comparableObject[T]](slice []T, element T) bool {
 	return false
 }
 
-func IsValidDomain(domain string) bool {
-	if domain == "" {
-		return false
-	}
-	return domainRegex.MatchString(domain)
-}