Importing boot-resources always bring back the full set of resources

I'd like to bootstrap MAAS as quickly as possible so I want to fetch as few boot-resources as possible. I need Jammy ga-22.04 for amd64 only so here's what I try to get that only:

```
# maas admin boot-source-selections create 1 os=ubuntu release=jammy arches=amd64 subarches="ga-22.04" labels="*"
Success.
Machine-readable output follows:
{
    "os": "ubuntu",
    "release": "jammy",
    "arches": [
        "amd64"
    ],
    "subarches": [
        "ga-22.04"
    ],
    "labels": [
        "*"
    ],
    "boot_source_id": 1,
    "id": 2,
    "resource_uri": "/MAAS/api/2.0/boot-sources/1/selections/2/"
}
# maas admin boot-resources import
```

However, the `import` brings back the full set of images:

```
# maas admin boot-resources read | jq -r '.[] | select(.name | contains("ubuntu/jammy"))'
{
  "id": 17,
  "type": "Synced",
  "name": "ubuntu/jammy",
  "architecture": "amd64/ga-22.04",
  "resource_uri": "/MAAS/api/2.0/boot-resources/17/",
  "subarches": "generic,hwe-p,hwe-q,hwe-r,hwe-s,hwe-t,hwe-u,hwe-v,hwe-w,ga-16.04,ga-16.10,ga-17.04,ga-17.10,ga-18.04,ga-18.10,ga-19.04,ga-19.10,ga-20.04,ga-20.10,ga-21.04,ga-21.10,ga-22.04"
}
{
  "id": 25,
  "type": "Synced",
  "name": "ubuntu/jammy",
  "architecture": "amd64/ga-22.04-lowlatency",
  "resource_uri": "/MAAS/api/2.0/boot-resources/25/",
  "subarches": "generic,hwe-p,hwe-q,hwe-r,hwe-s,hwe-t,hwe-u,hwe-v,hwe-w,ga-16.04,ga-16.10,ga-17.04,ga-17.10,ga-18.04,ga-18.10,ga-19.04,ga-19.10,ga-20.04,ga-20.10,ga-21.04,ga-21.10,ga-22.04"
}
{
  "id": 26,
  "type": "Synced",
  "name": "ubuntu/jammy",
  "architecture": "amd64/hwe-22.04",
  "resource_uri": "/MAAS/api/2.0/boot-resources/26/",
  "subarches": "generic,hwe-p,hwe-q,hwe-r,hwe-s,hwe-t,hwe-u,hwe-v,hwe-w,ga-16.04,ga-16.10,ga-17.04,ga-17.10,ga-18.04,ga-18.10,ga-19.04,ga-19.10,ga-20.04,ga-20.10,ga-21.04,ga-21.10,ga-22.04"
}
{
  "id": 27,
  "type": "Synced",
  "name": "ubuntu/jammy",
  "architecture": "amd64/hwe-22.04-edge",
  "resource_uri": "/MAAS/api/2.0/boot-resources/27/",
  "subarches": "generic,hwe-p,hwe-q,hwe-r,hwe-s,hwe-t,hwe-u,hwe-v,hwe-w,ga-16.04,ga-16.10,ga-17.04,ga-17.10,ga-18.04,hwe-18.10,hwe-19.04,hwe-19.10,hwe-20.04,hwe-22.04"
}
{
  "id": 28,
  "type": "Synced",
  "name": "ubuntu/jammy",
  "architecture": "amd64/hwe-22.04-lowlatency",
  "resource_uri": "/MAAS/api/2.0/boot-resources/28/",
  "subarches": "generic,hwe-p,hwe-q,hwe-r,hwe-s,hwe-t,hwe-u,hwe-v,hwe-w,ga-16.04,ga-16.10,ga-17.04,ga-17.10,ga-18.04,ga-18.10,ga-19.04,ga-19.10,ga-20.04,ga-20.10,ga-21.04,ga-21.10,ga-22.04"
}
{
  "id": 29,
  "type": "Synced",
  "name": "ubuntu/jammy",
  "architecture": "amd64/hwe-22.04-lowlatency-edge",
  "resource_uri": "/MAAS/api/2.0/boot-resources/29/",
  "subarches": "generic,hwe-p,hwe-q,hwe-r,hwe-s,hwe-t,hwe-u,hwe-v,hwe-w,ga-16.04,ga-16.10,ga-17.04,ga-17.10,ga-18.04,hwe-18.10,hwe-19.04,hwe-19.10,hwe-20.04,hwe-22.04"
}
```

# Additional information

```
# snap list maas maas-test-db
Name Version Rev Tracking Publisher Notes
maas 3.3.3-13184-g.3e9972c19 27405 3.3/stable canonical✓ -
maas-test-db 14.2-29-g.ed8d7f2 131 3.3/stable canonical✓ -
```