chore: removing more occurences of jest-fetch-mock and node-fetch

plugins/proxy-backend/package.json

@@ -27,7 +27,6 @@
     "express-promise-router": "^3.0.3",
     "http-proxy-middleware": "^0.19.1",
     "morgan": "^1.10.0",
-    "node-fetch": "^2.6.0",
     "uuid": "^8.0.0",
     "winston": "^3.2.1",
     "yaml": "^1.9.2",
@@ -40,7 +39,6 @@
     "@types/supertest": "^2.0.8",
     "@types/uuid": "^8.0.0",
     "@types/yup": "^0.28.2",
-    "jest-fetch-mock": "^3.0.3",
     "supertest": "^4.0.2"
   },
   "files": [