Actions `cluster:admin/repository/analyze/blob` and `cluster:admin/repository/analyze/register` and so on are only invoked via the transport service, they do not need to register as client actions so we can drop the `ActionType` instance. Instead the root `RepositoryAnalyzeAction` should create and register all these transport actions itself. But even the root `RepositoryAnalyzeAction` should not be an `ActionType` derivative, we should just declare an `ActionType` instance directly. Moreover we can use `ActionType#localOnly` since the client action does not run on remote clusters.
x-pack/plugin/snapshot-repo-test-kit/src/main/java/org/elasticsearch/repositories/blobstore/testkit/SnapshotRepositoryTestKit.java
public List<ActionHandler<? extends ActionRequest, ? extends ActionResponse>> getActions() {
        return List.of(
            new ActionHandler<>(RepositoryAnalyzeAction.INSTANCE, RepositoryAnalyzeAction.TransportAction.class),
            new ActionHandler<>(BlobAnalyzeAction.INSTANCE, BlobAnalyzeAction.TransportAction.class),
            new ActionHandler<>(GetBlobChecksumAction.INSTANCE, GetBlobChecksumAction.TransportAction.class),
            new ActionHandler<>(ContendedRegisterAnalyzeAction.INSTANCE, ContendedRegisterAnalyzeAction.TransportAction.class),
            new ActionHandler<>(UncontendedRegisterAnalyzeAction.INSTANCE, UncontendedRegisterAnalyzeAction.TransportAction.class)
        );
    }
    @Override
    public List<RestHandler> getRestHandlers(
        Settings settings,
        RestController restController,
        ClusterSettings clusterSettings,
        IndexScopedSettings indexScopedSettings,
        SettingsFilter settingsFilter,
        IndexNameExpressionResolver indexNameExpressionResolver,
        Supplier<DiscoveryNodes> nodesInCluster
    ) {
        return List.of(new RestRepositoryAnalyzeAction());
    }
    static void humanReadableNanos(XContentBuilder builder, String rawFieldName, String readableFieldName, long nanos) throws IOException {
        assert rawFieldName.equals(readableFieldName) == false : rawFieldName + " vs " + readableFieldName;
        if (builder.humanReadable()) {
            builder.field(readableFieldName, TimeValue.timeValueNanos(nanos).toHumanReadableString(2));
        }
        builder.field(rawFieldName, nanos);
    }
}