Update .NET SDK to 8.0.419 to resolve security vulnerability

Update from .NET SDK 8.0.303 to 8.0.419 (March 10, 2026) to address:
- CVE-2026-0847: RCE in ASP.NET Core SignalR (malformed WebSocket frames)
- CVE-2026-0848: DoS via .NET runtime GC (large object allocations)
- KB5081277 security update

Resolves S360 Component Governance alert DOTNET-Security-8.0.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: TravisEz13

global.json

@@ -1,6 +1,6 @@
 {
     "sdk": {
-        "version": "8.0.303",
+        "version": "8.0.419",
         "rollForward": "latestMajor"
     }
 }