Noticed in https://github.com/dotnet/installer/pull/18409 that errors aren't propagated which resulted in builds not to fail.
The fix here is to use `OnError` in the correct target (but only when using the minimal console log feature) and not set `IgnoreStandardErrorWarningFormat=true` on the Exec task that invokes the repo build script.
I also cleaned targets up as those introduced unnecessary complexity and logged in cases when they shouldn't (i.e. in dotnet.proj or package-source-build.proj).
This affected runtime which errors after 30s of building because of RuntimeOS and BaseOS being passed in in-correctly. Regressed with cca2b7bede (diff-86602308e6bb519266bc2f224ea65e39589d273804d40ad0f9c6e0eea2a263dc). Fixed that in runtime.proj. Kudos to Alexander who made the fix. I just copied it in form his CI PR.
