chore(api): Add signin config value
chore(api): Add signin config value

mozilla/fxa-auth-server,eoger/fxa-auth-server,TDA/fxa-auth-server,shane-tomlinson/fxa-auth-server,eoger/fxa-auth-server,eoger/fxa-auth-server,TDA/fxa-auth-server,TDA/fxa-auth-server,shane-tomlinson/fxa-auth-server,shane-tomlinson/fxa-auth-server,mozilla/fxa-auth-server,mozilla/fxa-auth-server,shane-tomlinson/fxa-auth-server,eoger/fxa-auth-server,mozilla/fxa-auth-server,TDA/fxa-auth-server