Azure subscription list for creating a new role

I am creating a new custom Azure role and trying to pass all the subscription IDs to the assignable scope argument using the below code but I am having issues converting from list to string with the correct string format. Here is the role definition module doc -

Appreciate any inputs or guidance!

locals {
 subscription_list  = formatlist("/subscriptions/%s", data.azurerm_subscriptions.all.subscriptions[*].subscription_id)
  quoted_subsciption_list = formatlist("%q", local.sub_list)

When I use join function to convert this into a string using the below code,
join(",", local.quoted_subsciption_list)

I am getting the output as “”/subscriptions/7yed1028-4525-4533-b608-fb74c2a9c1rr","/subscriptions/7uef9fad-dabf-8icf-8379-a3df99e7613c",

I want the output to be “/subscriptions/7yed1028-4525-4533-b608-fb74c2a9c1rr”, “/subscriptions/7uef9fad-dabf-8icf-8379-a3df99e7613c”.