Pathexpand all factory data paths (#3033)

* Pathexpand all factory data paths

* fix net monitoring paths

* fix file paths

---------

Co-authored-by: Ludovico Magnocavallo <ludomagno@google.com>

modules/project/iam.tf

@@ -20,10 +20,11 @@
 # - external users need to have accepted the invitation email to join
 
 locals {
+  _custom_roles_path = pathexpand(coalesce(var.factories_config.custom_roles, "-"))
   _custom_roles = {
-    for f in try(fileset(var.factories_config.custom_roles, "*.yaml"), []) :
+    for f in try(fileset(local._custom_roles_path, "*.yaml"), []) :
     replace(f, ".yaml", "") => yamldecode(
-      file("${var.factories_config.custom_roles}/${f}")
+      file("${local._custom_roles_path}/${f}")
     )
   }
   _iam_principal_roles = distinct(flatten(values(var.iam_by_principals)))