Use sdk.paths in global.json (#15258)

Co-authored-by: Jakub Jareš <me@jakubjares.com>

Author: Youssef1313

global.json

@@ -1,6 +1,11 @@
 {
   "sdk": {
     "version": "10.0.100-preview.7.25372.107",
+    "paths": [
+      ".dotnet",
+      "$host$"
+    ],
+    "errorMessage": "The .NET SDK could not be found, please run ./build.cmd on Windows or ./build.sh on Linux and macOS.",
     "rollForward": "minor",
     "allowPrerelease": false,
     "architecture": "x64"