remove readonly flag on schedules property for CI (#21653)

Co-authored-by: Naman Agarwal <[email protected]>

Author: namanag16

specification/machinelearningservices/resource-manager/Microsoft.MachineLearningServices/preview/2022-12-01-preview/machineLearningServices.json

@@ -3805,8 +3805,7 @@
         "schedules": {
           "description": "The list of schedules to be applied on the computes.",
           "$ref": "#/definitions/ComputeSchedules",
-          "x-nullable": true,
-          "readOnly": true
+          "x-nullable": true
         },
         "idleTimeBeforeShutdown": {
           "type": "string",