fix: Removed the default value of prefix input variable for roks quickstart variation (#1043)

Author: piyush117

patterns/roks-quickstart/variables.tf

@@ -11,7 +11,6 @@ variable "ibmcloud_api_key" {
 variable "prefix" {
   description = "A unique identifier for resources that is prepended to resources that are provisioned. Must begin with a lowercase letter and end with a lowercase letter or number. Must be 13 or fewer characters."
   type        = string
-  default     = "lz-roks-qs"
 
   validation {
     error_message = "Prefix must begin with a letter and contain only lowercase letters, numbers, and - characters. Prefixes must end with a lowercase letter or number and be 13 or fewer characters."