[macos] Shipping dotnet-* tools unsigned

[sdmaclea]

Description

The released global diagnostic tools are not signed.

For instance

codesign -v $(which dotnet-sos)

% codesign -v $(which dotnet-sos)
/Users/stmaclea/.dotnet/tools/dotnet-sos: code object is not signed at all
In architecture: arm64

This is problematic for Apple Silicon because it runs on Big Sur and the kernel will automatically kill all unsigned binaries.

zsh: killed    /Users/stmaclea/.dotnet/tools/dotnet-sos

It is not clear whether this affects all Big-Sur architectures.

/cc @hoyosjs @mikem8361 @vitek-karas

[tommcdon]

Move to future though will validate if this is already happening and if so close it