feat: Parse screenName in ProvidedUserInfo

This is available when having multiple providers where it provides
a screen name such as Twitter or GitHub.

See
https://cloud.google.com/identity-platform/docs/reference/rest/v1/ProviderUserInfo
for details.

It's available at endpoints like accounts.lookup or
projects.queryAccounts

Signed-off-by: Enrique J. Hernández <sixstone-qq@users.noreply.github.com>

Author: sixstone-qq

auth/user_mgt.go

@@ -59,6 +59,9 @@ type UserInfo struct {
 	// In UserRecord.UserInfo it will return the constant string "firebase".
 	ProviderID string `json:"providerId,omitempty"`
 	UID        string `json:"rawId,omitempty"`
+	// ScreenName is the user's screen name at Twitter or login name at GitHub.
+	// Only populated in ProviderUserInfo[]
+	ScreenName string `json:"screenName,omitempty"`
 }
 
 // multiFactorInfoResponse describes the `mfaInfo` of the user record API response

auth/user_mgt_test.go

@@ -57,6 +57,10 @@ var testUser = &UserRecord{
 			ProviderID:  "phone",
 			PhoneNumber: "+1234567890",
 			UID:         "testuid",
+		}, {
+			ProviderID: "github",
+			ScreenName: "login",
+			UID:        "testuid",
 		},
 	},
 	TokensValidAfterMillis: 1494364393000,
@@ -1926,6 +1930,10 @@ func TestMakeExportedUser(t *testing.T) {
 				ProviderID:  "phone",
 				PhoneNumber: "+1234567890",
 				UID:         "testuid",
+			}, {
+				ProviderID: "github",
+				ScreenName: "login",
+				UID:        "testuid",
 			}},
 		MFAInfo: []*multiFactorInfoResponse{
 			{

testdata/get_user.json

@@ -20,6 +20,11 @@
           "providerId": "phone",
           "phoneNumber": "+1234567890",
           "rawId": "testuid"
+        },
+        {
+          "providerId": "github",
+          "screenName": "login",
+          "rawId": "testuid"
         }
       ],
       "photoUrl": "http://www.example.com/testuser/photo.png",

testdata/list_users.json

@@ -20,6 +20,11 @@
                     "providerId": "phone",
                     "phoneNumber": "+1234567890",
                     "rawId": "testuid"
+                },
+                {
+                    "providerId": "github",
+                    "screenName": "login",
+                    "rawId": "testuid"
                 }
             ],
             "photoUrl": "http://www.example.com/testuser/photo.png",
@@ -66,6 +71,11 @@
                     "providerId": "phone",
                     "phoneNumber": "+1234567890",
                     "rawId": "testuid"
+                },
+                {
+                    "providerId": "github",
+                    "screenName": "login",
+                    "rawId": "testuid"
                 }
             ],
             "photoUrl": "http://www.example.com/testuser/photo.png",