Ensure relays don't make multiple connections during bootstrap

In update_consensus_networkstatus_downloads, relays use ClientBootstrapConsensusMaxInProgressTries as the maximum number of in-progress attempts, even though this value should only be used for clients.

(However, relays do not deliberately launch multiple attempts, so the impact of this bug should be minimal. Still, we should fix this to defend against bugs like #20499 (moved).)