Lightly refactor service agents locals in project module (#3380)

* lightly refactor project module service agent locals

* remove debug block

* tfdoc

* revert templatestring to format for universe kms

* reinstate moved block

modules/project/main.tf

@@ -73,8 +73,12 @@ locals {
     ? "${local.prefix}${var.name}"
     : "${local.universe_prefix}${local.prefix}${var.name}"
   )
-  universe_prefix    = var.universe == null ? "" : "${var.universe.prefix}:"
-  available_services = tolist(setsubtract(var.services, try(var.universe.unavailable_services, [])))
+  universe_prefix = var.universe == null ? "" : "${var.universe.prefix}:"
+  # available services are those declared, minus any unsupported by universe
+  available_services = tolist(setsubtract(
+    var.services,
+    try(var.universe.unavailable_services, [])
+  ))
 }
 
 data "google_project" "project" {