Use RtlGetVersion for Windows version checks

[Allerek]

Summary

Replaces the VerifyVersionInfoW-based Windows version check in SharedUtil::IsWindowsVersionOrGreater with RtlGetVersion.

This keeps the function aligned with its existing intent: return the real Windows version while ignoring compatibility mode shims.

VerifyVersionInfoW has also been deprecated by Microsoft all the way back in Windows 10.

Motivation

VerifyVersionInfoW can be affected by application compatibility/version manifest behavior, which can make OS version checks unreliable. RtlGetVersion returns the actual OS version from ntdll.dll, so this is a better fit for IsWindowsVersionOrGreater.

Test plan

Run on machines using Windows XP->Windows 7 SP-Whatever

Checklist

• Your code should follow the coding guidelines.
• Smaller pull requests are easier to review. If your pull request is beefy, your pull request should be reviewable commit-by-commit.

[Allerek]

Same as #4998 due to active discussion on Discord.