Add build.sh parameter to enable CleanWhileBuilding msbuild option

[MichaelSimons]

CleanWhileBuilding has a dramatic reduces the disk space requirements while building. We have had numerous distro maintainers encounter disk space issues in their CI (e.g. latest example). To help prevent these issues, we should explore ways to make this setting more visible. My recommendation is to add a parameter to build.sh to expose this setting.

[dotnet-issue-labeler]

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