bug: Ensure user profile fields are strings

In some cases id from the auth provider might be a int id, in that case wikijs won't accept it. Now, by converting it to strings it works, same for displayName

server/modules/authentication/oauth2/authentication.js

@@ -27,9 +27,9 @@ module.exports = {
           providerKey: req.params.strategy,
           profile: {
             ...profile,
-            id: _.get(profile, conf.userIdClaim),
+            id: String(_.get(profile, conf.userIdClaim)),
-            displayName: _.get(profile, conf.displayNameClaim, '???'),
+            displayName: String(_.get(profile, conf.displayNameClaim, '???')),
-            email: _.get(profile, conf.emailClaim),
+            email: String(_.get(profile, conf.emailClaim)),
             picture: picture
           }
         })