Added mocha as devDependency

Author: pajoma

package.json

@@ -341,7 +341,8 @@
     "esbuild": "^0.24.0",
     "typescript": "^5.6.3",
     "@vscode/test-cli": "^0.0.10",
-    "@vscode/test-electron": "^2.4.1"
+    "@vscode/test-electron": "^2.4.1",
+    "mocha": "^10.8.2"
   },
   "dependencies": {
     "@vscode/extension-telemetry": "^0.5.0",