refactor: Update the logic for prefix variable.

ibm_catalog.json

@@ -116,7 +116,8 @@
               ]
             },
             {
-              "key": "prefix"
+              "key": "prefix",
+              "required": true
             },
             {
               "key": "skip_iam_account_settings"

solutions/account-infrastructure-base/variables.tf

@@ -27,13 +27,13 @@ variable "region" {
 variable "prefix" {
   type        = string
   description = "An optional prefix to append to all resources created by this solution. If `provision_atracker_cos` is true, this value will be converted to lowercase in all instances."
-  default     = null
+  default     = "acc-infra-base"
 
   # prefix restriction due to limitations when using multiple DAs in stacks
   # this value was determined based on the lowest prefix restriction located here:
   # https://github.com/terraform-ibm-modules/terraform-ibm-landing-zone/blob/main/patterns/roks/variables.tf#L11
   validation {
-    condition     = var.prefix == null || can(length(var.prefix)) && length(var.prefix) <= 13
+    condition     = var.prefix == null || var.prefix == "" || can(length(var.prefix)) && length(var.prefix) <= 13
     error_message = "`prefix` length must be 13 characters or less or null."
   }
 }