[release/2.1] Include transitive refs in meta-package .nuspec files (#30639)

* Correct and streamline internal builds
- correct manual internal builds
    - need to explicitly set `$(BuildNumber)` property in all build steps
    - rename `$(BuildScriptArgs)` to avoid circular reference
- skip tests by default in internal non-PR builds

nits:
- include new `$(BuildNumberArg)` in `$(SharedFxArgs)`
- run all test jobs in internal pull requests

* Always skip tests in SharedFx and later jobs
- however test\SharedFx.UnitTests\SharedFx.UnitTests.csproj always runs as part of `BuildSharedFx` target

* Include transitive refs in meta-package .nuspec files
- #30279
- ensure dependencies are up-to-date even when PatchConfig.props is empty
- change only CoreFx and core-setup dependencies
- also change transitive references that weren't mentioned before

* Bump a few patch versions