Make repository signature verification blocking

[isidorn]

1. Make repository signature blocking on Windows and Mac
2. Make repository signature blocking on Linux
   • Investigate SIGSYS errors on Linux (dependency on https://github.com/microsoft/vscode-internalbacklog/issues/4998)
   • Find reproducible steps for Linux SIGSYS error
   • Fix SIGSYS error happening on linux. And make verification blocking

fyi @joaomoreno

[sandy081]

Using dat from last 2 stable version (1.91, 1.92)

Non Linux Platforms has 99.9% verification success rate

Whereas Linux platform has 94.4% success rate and 5.5% unknown errors

Here is the classification of Unknown Errors in Linux

83.1% are SIGSYS errors - Which needs further investigation.

Here is my proposal

1. Make repository signature blocking in Non Linux Platforms
2. Investigate in parallel SIGSYS error first and other errors in Linux
3. Enable repository signature blocking in Linux platform once we fixed above errors.

[isidorn]

This proposal makes a lot of sense to me. Thank you for looking into the data, and let me know if I can help in any way with 2.