Allow team server config to be missing
Allow team server config to be missing

, default to welcome page if either the teamToken or teamServerURL is undefined.

vector-im/riot-web,martindale/vector,vector-im/vector-web,vector-im/riot-web,vector-im/vector-web,vector-im/vector-web,vector-im/vector-web,vector-im/vector-web,vector-im/riot-web,vector-im/riot-web,vector-im/riot-web,martindale/vector,vector-im/riot-web