chore: remove unused dependency istanbul (#4540)

Author: comawill

packages/api-client/package.json

@@ -35,7 +35,6 @@
     "concurrently": "7.4.0",
     "cross-env": "7.0.3",
     "dotenv": "16.0.3",
-    "istanbul": "1.1.0-alpha.1",
     "jest": "^29.0.3",
     "nock": "13.2.9",
     "nyc": "15.1.0",