The Quay Config Tool is not validating configurations for Github Enterprise Login

1. The config tool is not validating configurations for GitHub Enterprise Login in Quay v3.4.6 and 3.5.6. Same configurations are accepted on quay v3.3.

configurations:
~~~
FEATURE_GITHUB_BUILD: true
FEATURE_GITHUB_LOGIN: true
GITHUB_LOGIN_CONFIG:
CLIENT_ID: xxxxxxxxxxxxxxx
CLIENT_SECRET: xxxxxxxxxxxxxxx
GITHUB_ENDPOINT: https://github.example.com
GITHUB_TRIGGER_CONFIG:
CLIENT_ID: xxxxxxxxxxxxxxx
CLIENT_SECRET: xxxxxxxxxxxxxxx
GITHUB_ENDPOINT: https://github.example.com
~~~ 

2. After passing env. variable`IGNORE_VALIDATION=true`, the quay container does not start.
~~~
$ podman run -d --rm -p 80:8080 -p 443:8443 --name=quay -v /root/quay3.5/config:/conf/stack:Z -v /root/quay3.5/storage:/datastorage:Z registry.redhat.io/quay/quay-rhel8:v3.4.6 --IGNORE_VALIDATIONe
1deed18e21a822f5224661ac6ec50370b26d53d8b4649511eb4d492de58a59be

$ podman run -d --rm -p 80:8080 -p 443:8443 --name=quay -v /root/quay3.5/config:/conf/stack:Z -v /root/quay3.5/storage:/datastorage:Z registry.redhat.io/quay/quay-rhel8:v3.5.6 --IGNORE_VALIDATION=true
51b88b9b914230a726000525fcf83a07841ce685287d247f89e0c59f6910ab91

$ podman ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
0e90bc43e07d registry.redhat.io/rhel8/postgresql-10:1 run-postgresql 33 hours ago Up 33 hours ago 0.0.0.0:5432->5432/tcp postgresql-quay
586ef2440b2e registry.redhat.io/rhel8/redis-5:1 run-redis 33 hours ago Up 33 hours ago 0.0.0.0:6379->6379/tcp redis
~~~