Resource pack resets after entering configuration phase

Description

After receiving a ClientboundStartConfigurationPacket the client appears to reset it's current server resource pack, although there is no other server resource pack sent during the configuration phase. For server networks with a server resource pack, this might become a problem, as they can't send a re-configuration packet without reloading resources twice (maybe only once if the resource pack is sent during the configuration phase, haven't tested it).

I'm not sure if this change was intended with the switch to the configuration network phase (like the deletion of chat messages MC-265250), but I don't think the resource pack should reset on every configuration change (without leaving the server).