chore(deps): remove unused vso-node-api dependency

The deprecated vso-node-api package was not used anywhere in the
codebase. Removing it entirely rather than migrating to azure-devops-node-api.

Author: JamieMagee

package-lock.json

@@ -73,7 +73,6 @@
     "throat": "^6.0.2",
     "tiny-attribution-generator": "0.1.3",
     "tmp": "0.2.5",
-    "vso-node-api": "6.5.0",
     "winston": "^3.17.0",
     "xml2js": "0.6.2"
   },