Improve name validation for cluster

app/validators/cluster_name_validator.rb

@@ -3,11 +3,7 @@
 # Custom validator for ClusterName.
 class ClusterNameValidator < ActiveModel::EachValidator
   def validate_each(record, attribute, value)
-    if record.user?
-      unless value.present?
-        record.errors.add(attribute, " has to be present")
-      end
-    elsif record.gcp?
+    if record.managed?
       if record.persisted? && record.name_changed?
         record.errors.add(attribute, " can not be changed because it's synchronized with provider")
       end
@@ -19,6 +15,10 @@ class ClusterNameValidator < ActiveModel::EachValidator
       unless value =~ Gitlab::Regex.kubernetes_namespace_regex
         record.errors.add(attribute, Gitlab::Regex.kubernetes_namespace_regex_message)
       end
+    else
+      unless value.present?
+        record.errors.add(attribute, " has to be present")
+      end
     end
   end
 end