how to change timeout parameter on steps of web scenarios using the API and PS

[maco1717]

I am trying to updated the timeout parameter on all step of the web scenarios in a host to a certain value using PowerShell but I am getting an getting the following error

jsonrpc : 2.0
error : @{code=-32602; message=Invalid params.; data=Invalid parameter "/1/steps/1": an array is expected.}
id : 1

my script is the following

$ZabbixServerEndpointUri = "..."

$body = @{
   "jsonrpc" = "2.0"
   "method" = "httptest.get"
   "params" = @{
      "filter"= @{
         "httptestid"= 382
      }
      "selectSteps" = "extend"
      "output" = "extend"
   }
   "auth" = ""
   "id" = 1
}
$JSON_reponse = Invoke-RestMethod -Uri $ZabbixServerEndpointUri -Body ($body | ConvertTo-json) -method POST -ContentType "application/json"
$body = @{
    "jsonrpc" = "2.0"
    "method" = "httptest.update"
    "params" = @{
        "httptestid" = $JSON_reponse.result.httptestid
        "steps" = @()
    }
    "auth" = "..."
    "id" = 1
}
$body.params.steps = [array]@($JSON_reponse.result.steps | foreach-object {$_.timeout ="5s";$_})
$JSON_result = Invoke-RestMethod -Uri $ZabbixServerEndpointUri -Body ($body2 | ConvertTo-json) -method POST -ContentType "application/json"
$JSON_result

I am not sure where the error is coming from. Any advice? I have checked the data type of $body.params.steps and it look correct.