Add back [OAuth2 idTokenWhitelistFields default empty array](https://github.com/wekan/wekan/commit/8b31c0768c34fc4557b54cec936a0b4288a8e722#commitcomment-33921882).

Thanks to moserben16 !

server/authentication.js

@@ -76,7 +76,7 @@ Meteor.startup(() => {
             authorizationEndpoint: process.env.OAUTH2_AUTH_ENDPOINT,
             userinfoEndpoint: process.env.OAUTH2_USERINFO_ENDPOINT,
             tokenEndpoint: process.env.OAUTH2_TOKEN_ENDPOINT,
-            idTokenWhitelistFields: process.env.OAUTH2_ID_TOKEN_WHITELIST_FIELDS,
+            idTokenWhitelistFields: process.env.OAUTH2_ID_TOKEN_WHITELIST_FIELDS || [],
             requestPermissions: process.env.OAUTH2_REQUEST_PERMISSIONS,
           },
           // OAUTH2_ID_TOKEN_WHITELIST_FIELDS || [],