[Crash Consistent RestorePoints] Making consistencyMode input parameter for RestorePoint (#18165)

* removing readonly for consistencymode

* small spell correction 2.1

Author: prchin

specification/compute/resource-manager/Microsoft.Compute/stable/2022-03-01/ComputeRP/restorePoint.json

@@ -864,7 +864,6 @@
         },
         "consistencyMode": {
           "type": "string",
-          "readOnly": true,
           "enum": [
             "CrashConsistent",
             "FileSystemConsistent",
@@ -874,7 +873,7 @@
             "name": "ConsistencyModeTypes",
             "modelAsString": true
           },
-          "description": "Gets the consistency mode for the restore point. Please refer to https://aka.ms/RestorePoints for more details."
+          "description": "ConsistencyMode of the RestorePoint. Can be specified in the input while creating a restore point. For now, only CrashConsistent is accepted as a valid input. Please refer to https://aka.ms/RestorePoints for more details."
         },
         "timeCreated": {
           "type": "string",