Introduce iam_by_principals_conditional (#3649)

* Introduce iam_by_principals_conditional

* Add iam_by_principals_conditional to project factory

* Update IAM ADR

* Update project factory readme

* Sync FAST schemas

* Update organization schema

* Add resman tests for iam_by_principals_conditional

* Update PF project-defaults.tf

* Update copyright

modules/project-factory/variables-folders.tf

@@ -1,5 +1,5 @@
 /**
- * Copyright 2025 Google LLC
+ * Copyright 2026 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -40,6 +40,14 @@ variable "folders" {
       }))
     })), {})
     iam_by_principals = optional(map(list(string)), {})
+    iam_by_principals_conditional = optional(map(object({
+      roles = list(string)
+      condition = object({
+        expression  = string
+        title       = string
+        description = optional(string)
+      })
+    })), {})
     pam_entitlements = optional(map(object({
       max_request_duration = string
       eligible_users       = list(string)