[bug] Bridge and VLAN interaction

Describe the bug
A clear and concise description of the bug or unexpected behavior.

Steps To Reproduce
Steps to reproduce the behavior:

1. Create a template:

{
    "interfaces": [
        {
            "type": "bridge",
            "stp": false,
            "bridge_members": [
                "cpwlan0",
                "cpwlan1"
            ],
            "name": "br-wifi",
            "network": "wifi"
        },
        {
            "wireless": {
                "network": [
                    "wifi"
                ],
                "mode": "access_point",
                "radio": "radio0",
                "ssid": "SSID HERE",
                "encryption": {
                    "protocol": "none"
                },
                "wmm": true,
                "isolate": true,
                "macfilter": "disable",
                "maclist": []
            },
            "type": "wireless",
            "name": "cpwlan0"
        },
        {
            "wireless": {
                "network": [
                    "wifi"
                ],
                "mode": "access_point",
                "radio": "radio1",
                "ssid": "SSID HERE",
                "encryption": {
                    "protocol": "none"
                },
                "wmm": true,
                "isolate": true,
                "macfilter": "disable",
                "maclist": []
            },
            "type": "wireless",
            "name": "cpwlan1"
        },
        {
            "type": "8021q",
            "name": "br-wifi",
            "disabled": false,
            "vid": 200,
            "ingress_qos_mapping": [],
            "egress_qos_mapping": []
        }
    ]
}

2. Assign the template to a device
3. Look at the resulting configuration preview of the device and compare it with the config preview generated by the template

Result: they're not the same, the device conf is missing the br-wifi part.

Expected behavior
The resulting configuration is the same.

System Informatioon:

• OS: Ubuntu 24.04.1 LTS
• Python Version: Python 3.12.3 (main, Jan 17 2025, 18:03:48) [GCC 13.3.0] on linux

Reproduce the issue by assigning the provided template to a device, then compare the template configuration preview with the resulting device configuration preview. Focus on how the bridge and 802.1q interfaces sharing the br-wifi name are represented; done means the device configuration includes the same br-wifi VLAN-related configuration as the template.