Replaced nock usage in the oidc provider tests with msw

plugins/auth-backend/package.json

@@ -33,6 +33,7 @@
     "@backstage/catalog-client": "^0.3.6",
     "@backstage/catalog-model": "^0.7.2",
     "@backstage/config": "^0.1.3",
+    "@backstage/test-utils": "^0.1.8",
     "@types/express": "^4.17.6",
     "@types/passport": "^1.0.3",
     "compression": "^1.7.4",
@@ -77,8 +78,7 @@
     "@types/passport-saml": "^1.1.2",
     "@types/passport-strategy": "^0.2.35",
     "@types/xml2js": "^0.4.7",
-    "msw": "^0.21.2",
-    "nock": "^13.0.5"
+    "msw": "^0.21.2"
   },
   "files": [
     "dist",