Move debug package to devDependencies in typespec-vscode

The debug package is only used during development/build time for the
VSCode extension, not at runtime, so it should be in devDependencies
rather than dependencies.

Co-authored-by: RodgeFu <6038235+RodgeFu@users.noreply.github.com>

Author: Copilot

packages/typespec-vscode/package.json

@@ -310,9 +310,7 @@
     "vscode-languageclient": "~9.0.1",
     "which": "^6.0.0",
     "yaml": "~2.8.2",
-    "@types/debug": "~4.1.12"
-  },
-  "dependencies": {
+    "@types/debug": "~4.1.12",
     "debug": "~4.4.0"
   }
 }