dotnet7 packages are still available for installation in Ubuntu 22.04 but they're broken

I just noticed that in Ubuntu 22.04, dotnet7 is still available among the ubuntu apt packages that can be installed:

```
$ uname -a
Linux chayotebox 6.8.0-45-generic #45~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Wed Sep 11 15:25:05 UTC 2 x86_64 x86_64 x86_64 GNU/Linux

$ cat /etc/apt/sources.list.d/microsoft-prod.list
deb [arch=amd64,arm64,armhf] https://packages.microsoft.com/ubuntu/22.04/prod jammy main

$ sudo apt update
...

$ sudo apt install dotnet [pressed tab]
dotnet6 dotnet-hostfxr-3.1 dotnet-runtime-deps-6.0 dotnet-sdk-dbg-8.0
dotnet7 dotnet-hostfxr-6.0 dotnet-runtime-deps-7.0 dotnet-targeting-pack-6.0
dotnet8 dotnet-hostfxr-7.0 dotnet-runtime-deps-8.0 dotnet-targeting-pack-7.0
dotnet-apphost-pack-3.1 dotnet-hostfxr-8.0 dotnet-sdk-3.1 dotnet-targeting-pack-8.0
dotnet-apphost-pack-6.0 dotnet-runtime-3.1 dotnet-sdk-6.0 dotnet-templates-6.0
dotnet-apphost-pack-7.0 dotnet-runtime-6.0 dotnet-sdk-6.0-source-built-artifacts dotnet-templates-7.0
dotnet-apphost-pack-8.0 dotnet-runtime-7.0 dotnet-sdk-7.0 dotnet-templates-8.0
dotnet-host dotnet-runtime-8.0 dotnet-sdk-7.0-source-built-artifacts
dotnet-host-7.0 dotnet-runtime-dbg-8.0 dotnet-sdk-8.0
dotnet-host-8.0 dotnet-runtime-deps-3.1 dotnet-sdk-8.0-source-built-artifacts
```

But if I attempt to install `dotnet7` I get this message:
```
$ sudo apt install dotnet7
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
dotnet-hostfxr-7.0 : Depends: dotnet-host-7.0
E: Unable to correct problems, you have held broken packages.
```

The error makes me believe that since .NET 7 it's now out of support, we shouldn't offer broken packages in apt, so all packages should be removed.

Bonus: Just out of curiosity, I force-installed those two packages that had unmet dependencies, and now the whole `dotnet` stopped working unless I uninstall all dotnet7 packages.