Scaling Policy for Das is dropped without error when submitting job to OSS

If a user submits a job file that contains a DAS scaling policy, the job is registered without error or warning, and the policies are not persisted into the state store

job file

- `nomad job run example.nomad`
- `nomad scaling policy list`

```hcl
job "example" {
datacenters = ["dc1"]

group "cache-lb" {
count = 1

network {
port "lb" {
to = 6379
}
}

service {
name = "redis-lb"
port = "lb"
address_mode = "host"

check {
type = "tcp"
port = "lb"
interval = "10s"
timeout = "2s"
}
}

task "nginx" {
driver = "docker"

config {
image = "nginx"
ports = ["lb"]
volumes = [
# It's safe to mount this path as a file because it won't re-render.
"local/nginx.conf:/etc/nginx/nginx.conf",
# This path hosts files that will re-render with Consul Template.
"local/nginx:/etc/nginx/conf.d"
]
}

# This template overwrites the embedded nginx.conf file so it loads
# conf.d/*.conf files outside of the `http` block.
template {
data = <

Start by running `nomad job run example.nomad`, then use `nomad scaling policy list` to compare the submitted policies with the state store. The issue is done when DAS scaling policies in the job file are no longer silently dropped and are persisted or an appropriate error or warning is reported.

Written by the indexing model from the issue text.