fix: updated aws-backup layer to correct role permission and making monthly backup optional

modules/storage/aws-backup/variables.tf

@@ -6,6 +6,7 @@ variable "daily-backup-cron" {
 variable "monthly-backup-cron" {
   type        = string
   description = "Monthly backup rule cron expression"
+  default     = null
 }
 
 variable "daily-backup-retention" {
@@ -16,6 +17,7 @@ variable "daily-backup-retention" {
 variable "monthly-backup-retention" {
   type        = number
   description = "Monthly backup retention period"
+  default     = null
 }
 
 variable "service-opt-in" {
@@ -54,4 +56,16 @@ variable "service-opt-in" {
       enabled = false
     }
   }
+}
+
+variable "backup_kms_key" {
+  description = "KMS key arn for AWS Backup"
+  type        = string
+  default     = null
+}
+
+variable "enable-monthly-backup" {
+  description = "Enable monthly backup plan"
+  type        = bool
+  default     = false
 }