added a few unit test cases for registerAuth

Author: bhparijat

.changeset/small-chairs-explain.md

@@ -1,5 +1,5 @@
 ---
-'@firebase/auth': minor
+'@firebase/auth': patch
 ---
 
 Allow port numbers in authDomain

packages/auth/src/core/auth/initialize.test.ts

@@ -140,7 +140,7 @@ describe('core/auth/initialize', () => {
     fakeApp = initializeApp({
       apiKey: 'fake-key',
       appId: 'fake-app-id',
-      authDomain: 'fake-auth-domain'
+      authDomain: 'fake-auth-domain:9999'
     });
   });
 
@@ -165,7 +165,7 @@ describe('core/auth/initialize', () => {
         apiHost: 'identitytoolkit.googleapis.com',
         apiKey: 'fake-key',
         apiScheme: 'https',
-        authDomain: 'fake-auth-domain',
+        authDomain: 'fake-auth-domain:9999',
         clientPlatform: expectedClientPlatform,
         sdkClientVersion: expectedSdkClientVersion,
         tokenApiHost: 'securetoken.googleapis.com'