Nuget V3 Group packages incorrectly sorted in page causing some installs to fail

Description
When a Nuget v3 group repository merges the registration metadata, required fields upper and lower (https://docs.microsoft.com/en-us/nuget/api/registration-base-url-resource#registration-page-object) are filled incorrectly. NuGet uses these fields in the package installation process.

Reproduce
Following started with happens on version from OSS 3.27 and OSS 3.28

Setup

my-group as nuget-group
1) nuget-hosted
2) nuget.org v3 proxy 

nuget.config inside a VS 2019 solution

```
<?xml version="1.0" encoding="utf-8"?>
<configuration>
{{ <packageSources>}}
{{ <clear /> }}
{{ <add key="my-group" value="https://nexus.mydomain.tt/repository/nuget-group/index.json" />}}
{{ </packageSources>}}
{{ <packageSourceCredentials>}}
{{ <my-group>}}
{{ <add key="Username" value="nuget-read" />}}
{{ <add key="ClearTextPassword" value="somekey" />}}
{{ </my-group>}}
{{ </packageSourceCredentials>}}
</configuration>

```

Situation

After an cache-clear and removal of an installed package hosted by a private repository on nexus3 within visual studio 2019,

it can not be reinstalled with some kind of dependency error:

`Unable to find metadata of Microsoft.Win32.Primitives.4.3.0`

New Projects can find the hosted package and fail to install it with the same error.

Test

changed do order inside the my-group repository to:

1) nuget.org-proxy v3
2) nuget-hosted

After visual studio 2019 found all public packages but none private anymore.

Workaround

After adding the group and proxy repository into the nuget config the error went away.
```

<?xml version="1.0" encoding="utf-8"?>
<configuration>
{{ <packageSources>}}
{{ <clear /> }}
{{ <add key="my-group" value="https://}}nexus.mydomain.tt/repository/nuget-group/index.json" />
<add key="my-proxy" value="https://nexus.mydomain.tt/repository/nuget.org-proxy/index.json" />
{{ </packageSources>}}
{{ <packageSourceCredentials>}}
{{ <}}my-group>
<add key="Username" value="nuget-read" />
{{ <add key="ClearTextPassword" value="somekey" />}}
{{ </}}my-group>
{{ <}}my-proxy>
<add key="Username" value="nuget-read" />
{{ <add key="ClearTextPassword" value="somekey" />}}
{{ </}}my-proxy>
{{ </packageSourceCredentials>}}
</configuration>

```