Import of ubuntu:22.04 docker image fails with error

Reproduce steps:

1. create a proxy repository against dockerhub in 3.39.0
2. pull ubuntu:22.04 image through the proxy
3. export the repository to disk
4. create a hosted docker repository
5. import the exported repository into it
6. try to download "/v2/ubuntu/manifests/22.04" through the hosted repository

This will fail with an error.

2022-06-03 14:01:05,076-0500 WARN [qtp111228484-125] admin org.sonatype.nexus.repository.docker.internal.V2Handlers - Error: GET /v2/ubuntu/manifests/22.04
groovy.lang.MissingPropertyException: No such property: manifests for class: org.sonatype.nexus.repository.docker.internal.V2ManifestSchema2
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.unwrap(ScriptBytecodeAdapter.java:66)
at org.codehaus.groovy.runtime.callsite.ConstructorSite$NoParamSite.callConstructor(ConstructorSite.java:127)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallConstructor(CallSiteArray.java:59)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:238)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:250)
at org.sonatype.nexus.repository.docker.internal.datastore.recipe.V2ManifestUtilImpl.mayDowngrade(V2ManifestUtilImpl.groovy:177)
at org.sonatype.nexus.repository.docker.internal.datastore.recipe.DockerHostedFacetImpl.getManifestByTag(DockerHostedFacetImpl.java:610)
at org.sonatype.nexus.repository.docker.internal.DockerHostedFacet$getManifestByTag.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:144)
at org.sonatype.nexus.repository.docker.internal.V2Handlers$_closure14.doCall(V2Handlers.groovy:261)

The manifest that is referenced starts with "manifests" attribute:

{
    "manifests": [
        {
            "digest": "sha256:aa6c2c047467afc828e77e306041b7fa4a65734fe3449a54aa9c280822b0d87d",
            "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
            "platform": {
                "architecture": "amd64",
                "os": "linux"
            },
            "size": 529
        },
...

And the image pulls just fine directly using docker. So this is a bug in our code.

Expected: Nexus Repo should be able to correctly process any image manifest that works with docker.