wsl --update with --release specific version

**Is your feature request related to a problem? Please describe.**
Handle control of wsl --update versions in enterprise, having this option allows to install / update specific version without risks/hassle between versions.

Also it seems that wsl --update somehow does not requires Admin privileges, even if it's complains about it it will install / update anyway. That's good to avoid extra and tedious work to install WSL AppPackage in a script, launch a process as another account (which is admin) which tries to register the WSL specific version package....

**Describe the solution you'd like**
wsl --update does allow to get which version to update to, it just defaults to the latest stable release. However, would be really great to allow to pass an specific stable or prerelease version in certain scenarios when more control is needed (enterprise):

Something like:
```bash
wsl --update --version 2.0.9
```
or
```
wsl --update --release 2.0.9
```
**Describe alternatives you've considered**

**Additional context**

Start by tracing the existing `wsl --update` command and how it selects the latest stable or prerelease package. Define how a requested version such as `2.0.9` is accepted and validated, then verify that the command installs exactly that release without changing the current update behavior.

Written by the indexing model from the issue text.