Update DeploymentScripts swagger to address swagger correctness issues (Azure#11949)

Author: lwang2016

specification/resources/resource-manager/Microsoft.Resources/preview/2019-10-01-preview/deploymentScripts.json

@@ -606,7 +606,8 @@
         "timeout": {
           "type": "string",
           "format": "duration",
-          "description": "Maximum allowed script execution time specified in ISO 8601 format. Default value is PT1H"
+          "default": "P1D",
+          "description": "Maximum allowed script execution time specified in ISO 8601 format. Default value is P1D"
         }
       }
     },
@@ -633,6 +634,7 @@
             "OnSuccess",
             "OnExpiration"
           ],
+          "default": "Always",
           "x-ms-enum": {
             "name": "cleanupOptions",
             "modelAsString": true
@@ -771,10 +773,12 @@
       "description": "User-assigned managed identity.",
       "properties": {
         "principalId": {
+          "readOnly": true,
           "type": "string",
           "description": "Azure Active Directory principal ID associated with this identity."
         },
         "clientId": {
+          "readOnly": true,
           "type": "string",
           "description": "Client App Id associated with this identity."
         }

specification/resources/resource-manager/Microsoft.Resources/stable/2020-10-01/deploymentScripts.json

@@ -608,7 +608,8 @@
         "timeout": {
           "type": "string",
           "format": "duration",
-          "description": "Maximum allowed script execution time specified in ISO 8601 format. Default value is PT1H"
+          "default": "P1D",
+          "description": "Maximum allowed script execution time specified in ISO 8601 format. Default value is P1D"
         }
       }
     },
@@ -635,6 +636,7 @@
             "OnSuccess",
             "OnExpiration"
           ],
+          "default": "Always",
           "x-ms-enum": {
             "name": "cleanupOptions",
             "modelAsString": true
@@ -769,10 +771,12 @@
       "description": "User-assigned managed identity.",
       "properties": {
         "principalId": {
+          "readOnly": true,
           "type": "string",
           "description": "Azure Active Directory principal ID associated with this identity."
         },
         "clientId": {
+          "readOnly": true,
           "type": "string",
           "description": "Client App Id associated with this identity."
         }