Unable to assign policy_rules to a policy via RestAPI

[gneville-ot]

Environment

• Python version: 3.10
• Nautobot version: 1.5.18
• nautobot-plugin-firewall-model version: 1.2.1

Able to send a list of policy-rules to a policy via RestAPI so they can be attached.

API accepts call however the policy-rules aren't attached to the policy

Steps to Reproduce

1. Create policy-rules
2. Attempt to create or update a policy to attach policy-rules via RestAPI

A POST to http://localhost:8080/api/plugins/firewall/policy/ with this payload is accepted but policy-rules aren't attached:

{
    "name": "mypolicy",
    "description": "restrictive",
    "status": "active",
    "assigned_devices": [
      {
        "device": "d0562f91-37a6-413e-8b45-5756f6d784dc",
        "weight": 100
      }
    ],
    "policy_rules": [
       "58099d8e-badc-49b4-81d6-685db4c3186a"
    ]
}

A PATCH to http://localhost:8080/api/plugins/firewall/policy/859ff981-52bc-4980-a209-1243d2212ac2/) with this payload is accepted but policy-rules aren't attached:

{
    "policy_rules": [
       "58099d8e-badc-49b4-81d6-685db4c3186a"
    ]
}