fix: fixes failing CI build as cert is not configured

Default value should be false, and set to true when cert path is configured

Author: dcoric

proxy.config.json

@@ -136,7 +136,7 @@
   "csrfProtection": true,
   "plugins": [],
   "tls": {
-    "enabled": true,
+    "enabled": false,
     "key": "certs/key.pem",
     "cert": "certs/cert.pem"
   }

test/chain.test.js

@@ -15,7 +15,7 @@ const mockLoader = {
   ],
 };
 
-const initMockPushProcessors = () => {
+const initMockPushProcessors = (sinon) => {
   const mockPushProcessors = {
     parsePush: sinon.stub(),
     audit: sinon.stub(),