[dotnet] add proper support for preview versions

[sliekens]

Pull request #1305 added the ability to specify "version": "10.0-preview", however, the implementation does not actually honor the suffix. Instead, the suffix is simply removed.

features/src/dotnet/install.sh

Lines 111 to 112 in c05bd45

	# Remove '-preview' from version if suffixed with the version label
	clean_version="$(echo "$version" | sed 's/-preview$//')"

Once .NET 10 goes GA, that means 10.0-preview will also resolve to a GA build, and this could be surprising behavior.

Instead, I would recommend to modify the install script to add proper support for -preview as a suffix, such that it always results in a preview version getting installed.

The underlying dotnet-install.sh script allows this by passing flag --quality preview, it is just a matter of wiring it up properly.

dotnet-install.sh --channel 10.0 --quality preview

[sliekens]

Drafting a PR for this

cc @Kaniska244