Fix 101-synapse (#187)

* fix 101-synapse

Co-authored-by: zjhe <hezijie@microsoft.com>

quickstart/101-synapse/variables.tf

@@ -1,6 +1,7 @@
 variable "name" {
   type        = string
   description = "Name of the deployment"
+  default     = null
 }
 
 variable "environment" {
@@ -17,21 +18,24 @@ variable "location" {
 
 variable "aad_login" {
   description = "AAD login"
-  type = object({
+  type        = object({
     name      = string
     object_id = string
     tenant_id = string
   })
+  default = null
 }
 
 variable "synadmin_username" {
   type        = string
   description = "Specifies The login name of the SQL administrator"
+  default     = "synapseadmin"
 }
 
 variable "synadmin_password" {
   type        = string
   description = "The Password associated with the sql_administrator_login for the SQL administrator"
+  default     = null
 }
 
 variable "enable_syn_sparkpool" {
@@ -44,4 +48,10 @@ variable "enable_syn_sqlpool" {
   type        = bool
   description = "Variable to enable or disable Synapse Dedicated SQL pool deployment"
   default     = false
+}
+
+variable "msi_id" {
+  type    = string
+  description = "If you're running this example by authentication with identity, please set identity object id here."
+  default = null
 }