Fix RoutingSessionInfo route ID issue

In the previous CL, we relied on MediaRouterUtils.getOriginalId()
that returns a wrong ID when it has no provider ID but the separator.

Resolve the issue by resetting route ID in Builder class.

Bug: 150666870
Bug: 150751854
Test: cts test realted to MediaRouter2
Change-Id: Ib17cdc8385308ccadad79e117fcfede72b8af6b5