[Feature] Parameter for AutoUgrade Agent at FleetPolicy

[icefish-creativ]

At big automated Environments it is important to do that with terraform

could looks like this

resource "elasticstack_fleet_agent_policy" "autoagent" {
  name            = "autoagent"
  namespace       = "base"
  description     = "Policy for autoagent"
  sys_monitoring  = true
  required_versions = {
    "version" = {
       "string_value" = "8.19.2"
    }
    "percentage" = {
        "value" = 100
     }
  }
}